Off-Grid Laws by State: Rainwater, Greywater & Composting Toilets (2026)

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Not legal advice. This is a plain-English summary of state rules, checked November 2, 2026, with a link to the official source for each. Counties and cities can be stricter than the state, and rules change. Confirm with your county health department and building department before you build.

The short answer

Collecting rainwater from your roof is legal in every state; a handful (Colorado, Utah and a few others) cap how much you can store or what you can use it for. Greywater reuse is allowed in 32 states, usually with a permit or design limits. Composting toilets are allowed in most states, but most still require an approved septic or greywater system for sink and shower water. Off-grid solar is not banned anywhere; it falls under the electrical code (NEC edition) your state or county enforces.

Off-Grid Laws by State: All 50 States at a Glance

Click a state for the details and the official source behind each rating. “No state rule” means we found no statewide statute or regulation; local rules may still apply.

Allowed Allowed, limits Permit needed Restricted No state rule

State	Rainwater	Greywater	Composting toilets	Electrical code
Alabama	No state rule	Restricted	Allowed, limits	Local adoption
Alaska	No state rule	Permit needed	No state rule	NEC 2020
Arizona	No state rule	Allowed, limits	Permit needed	Local adoption
Arkansas	Allowed, limits	No state rule	Allowed, limits	NEC 2020
California	Allowed	Allowed, limits	No state rule	NEC 2023
Colorado	Allowed, limits	Permit needed	Allowed, limits	NEC 2023
Connecticut	No state rule	Restricted	Permit needed	NEC 2020
Delaware	No state rule	Permit needed	No state rule	NEC 2023
Florida	No state rule	Permit needed	Allowed, limits	NEC 2020
Georgia	Allowed, limits	Allowed, limits	No state rule	NEC 2023
Hawaii	Allowed	Allowed, limits	Allowed, limits	NEC 2020
Idaho	Allowed	Permit needed	Allowed, limits	NEC 2023
Illinois	No state rule	No state rule	Allowed, limits	Local adoption
Indiana	No state rule	Restricted	Allowed, limits	NEC 2008
Iowa	No state rule	No state rule	No state rule	NEC 2023
Kansas	No state rule	Restricted	No state rule	Local adoption
Kentucky	No state rule	Permit needed	Allowed, limits	NEC 2023
Louisiana	No state rule	No state rule	Permit needed	NEC 2020
Maine	No state rule	Permit needed	Permit needed	NEC 2023
Maryland	No state rule	Restricted	Permit needed	NEC 2023
Massachusetts	No state rule	Permit needed	Allowed, limits	NEC 2023
Michigan	No state rule	Permit needed	Permit needed	NEC 2023
Minnesota	Permit needed	Allowed, limits	Allowed, limits	NEC 2026
Mississippi	No state rule	No state rule	Allowed, limits	Local adoption
Missouri	No state rule	Allowed, limits	Allowed, limits	Local adoption
Montana	No state rule	Permit needed	Allowed, limits	NEC 2023
Nebraska	No state rule	Restricted	No state rule	NEC 2023
Nevada	Allowed, limits	Permit needed	No state rule	Local adoption
New Hampshire	No state rule	Restricted	Allowed, limits	NEC 2023
New Jersey	No state rule	Permit needed	Restricted	NEC 2023
New Mexico	Allowed	Allowed, limits	Allowed, limits	NEC 2020
New York	No state rule	Restricted	Allowed, limits	NEC 2023
North Carolina	Allowed	Permit needed	Permit needed	NEC 2020
North Dakota	No state rule	No state rule	No state rule	NEC 2023
Ohio	Permit needed	Permit needed	Allowed, limits	NEC 2023
Oklahoma	Allowed	Allowed, limits	No state rule	NEC 2023
Oregon	Allowed	Permit needed	Permit needed	NEC 2026
Pennsylvania	No state rule	Permit needed	Permit needed	NEC 2020
Rhode Island	No state rule	Restricted	Permit needed	NEC 2023
South Carolina	Allowed, limits	Permit needed	Permit needed	NEC 2020
South Dakota	No state rule	Allowed, limits	Permit needed	NEC 2023
Tennessee	Allowed, limits	No state rule	Allowed, limits	NEC 2017
Texas	Allowed	Allowed, limits	Permit needed	NEC 2026
Utah	Allowed, limits	Permit needed	No state rule	NEC 2023
Vermont	Allowed, limits	No state rule	Permit needed	NEC 2023
Virginia	Permit needed	No state rule	Allowed, limits	NEC 2020
Washington	Allowed, limits	Permit needed	Permit needed	NEC 2023
West Virginia	No state rule	Permit needed	Allowed, limits	NEC 2020
Wisconsin	No state rule	Permit needed	Allowed, limits	NEC 2023
Wyoming	No state rule	Permit needed	No state rule	NEC 2026

Rainwater Collection: What the Rules Actually Limit

No state makes it illegal to catch rain from your roof. Where rules exist, they usually do one of three things: cap the volume (Colorado allows two barrels totaling 110 gallons at most single-family homes, for outdoor use; Utah allows two 100-gallon containers without registering and up to 2,500 gallons with free registration), limit the use to outdoor or non-potable purposes, or set plumbing standards if the water comes inside. Western states with prior-appropriation water law are the strictest, because rain that would have reached a stream can belong to a downstream right-holder. A few states, including Texas, Oklahoma and Virginia, actively encourage harvesting. Our rainwater collection systems guide covers the hardware.

Greywater: Why Permits Are Common

Greywater is water from showers, bathroom sinks and washing machines (not toilets, and in most states not kitchen sinks). Because it can carry pathogens, most states regulate it as wastewater: simple laundry-to-landscape systems are often allowed without a permit, while anything with storage, pumps or indoor reuse needs one. Nine states in our table still treat greywater as wastewater that must go to a septic or sewer system, or allow it only in narrow cases. See greywater systems for off-grid homes for the designs these rules have in mind.

Composting Toilets: The Septic Catch

Most states allow composting toilets, typically requiring a unit certified to NSF/ANSI 41 and a plan for the finished compost. The catch is that a composting toilet only handles toilet waste: if the house has a shower, sink or washing machine, most states still require an approved septic or greywater system for that water, sometimes a reduced-size one. That is the biggest surprise for people planning a no-septic cabin. More on how they work in how composting toilets work.

Off-Grid Power and the Electrical Code

Living off the grid electrically is legal in every state. What applies is the electrical code: most states adopt an edition of the National Electrical Code (NEC), and Article 690 (solar PV) and Article 706 (energy storage) cover off-grid systems. Some states adopt the NEC for all buildings; others leave it to counties and cities, so a rural parcel may have no inspection requirement while the next county requires a permit for any solar install. The table lists each state’s edition and, where it differs, the newer official adoption we found. Sizing the system itself? Use our off-grid solar calculator.

State-by-State Off-Grid Rules and Official Sources

Alabama

Rainwater collection No state rule

No Alabama statute or rule on residential rainwater harvesting was found; a 2015 PNNL state survey lists Alabama as having no rainwater harvesting regulations. Check with your county health department for any local requirements.

PNNL-24347, Rainwater Harvesting: State Regulations and Technical Resources (2015), secondary

Greywater reuse Restricted

Alabama Department of Public Health rules treat graywater as sewage: at a single-family home it must go to the building sewer or to a separate subsurface effluent disposal field (at least 25% of the normal field size). The rule covers disposal only and makes no provision for reuse (Ala. Admin. Code r. 420-3-1-.64).

Composting toilets Allowed, limits

Composting toilets are allowed under Alabama Department of Public Health rules but must be certified by NSF or another ANSI-accredited organization (the rule says 'the appropriate NSF Standard' and does not name NSF/ANSI 41). If the site produces other sewage the toilet is not designed to handle, an approved onsite sewage system is still required, and liquid must go to a public or private sewer system (Ala. Admin. Code r. 420-3-1-.29, effective Feb. 13, 2023).

Ala. Admin. Code r. 420-3-1-.29, Composting, Incinerating, and Portable Toilets (Alabama Legislature)

Electrical code (off-grid solar and wiring) Local adoption

IAEI lists the 2020 NEC (effective July 1, 2022) as Alabama's adopted code but says it applies only to state buildings, schools and hotels; there is no statewide standard for private homes, so the local jurisdiction decides. No statewide rule on solar or off-grid systems was found. NFPA's enforcement map (as of August 3, 2026) lists: 2020 (7/1/2022), Alabama Division of Construction Management.

Checked 2026-11-02. Back to the table

Alaska

Rainwater collection No state rule

No Alaska statute or rule restricting residential rainwater collection was found; the 2015 PNNL state survey lists Alaska as having no rainwater harvesting regulations. Check with your local government for any local requirements.

PNNL-24347, Rainwater Harvesting: State Regulations and Technical Resources (2015), secondary

Greywater reuse Permit needed

Graywater is defined in Alaska's wastewater rules (18 AAC 72), which are administered by the Department of Environmental Conservation (DEC). A DEC presentation on the rules states that all wastewater systems must be registered or approved, and that design guidance for graywater systems will be developed further in DEC's installation manual. No graywater-specific permit exemption was confirmed.

Composting toilets No state rule

No Alaska rule specific to composting toilets or NSF/ANSI 41 was confirmed. DEC's pit privy fact sheet says privies meeting its setback and construction conditions do not have to be approved by or registered with DEC, and says graywater must not be dumped into a privy. Check with DEC and your local government.

Alaska DEC, Pit Privy fact sheet

Electrical code (off-grid solar and wiring) NEC 2020

IAEI lists the 2020 NEC (effective April 16, 2020) as Alaska's statewide minimum, adopted through the Division of Labor Standards and Safety; local jurisdictions may adopt newer editions. IAEI notes that outside Anchorage, Fairbanks and Juneau only a few state inspectors cover the state. This is a secondary, undated source and a newer edition may have been adopted since; not confirmed on an official state page. No statewide solar or off-grid rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2020 (4/16/2020).

Checked 2026-11-02. Back to the table

Arizona

Rainwater collection No state rule

No statewide permit requirement or volume limit for residential rainwater collection was confirmed. A 2015 PNNL survey lists the Arizona Department of Water Resources as the relevant agency and notes that cities and towns may fund rainwater harvesting programs.

PNNL-24347, Rainwater Harvesting: State Regulations and Technical Resources (2015), secondary

Greywater reuse Allowed, limits

ADEQ's Type 1 General Permit allows residential graywater reuse under 400 gallons per day without any notice, application or renewal, if 13 best-management practices are followed. These include drip or flood irrigation only (no spray), water kept on the property where it is generated, no surface irrigation of food plants except citrus and nut trees, and groundwater at least 5 feet down. Kitchen sink and dishwasher water are excluded (18 A.A.C. 9, Article 7). Larger systems need ADEQ permits.

University of Arizona Cooperative Extension / ADEQ gray water brochure

Composting toilets Permit needed

ADEQ has a general permit for composting toilet systems with design flows under 3,000 gallons per day (max 50 persons/day); a notice of intent is required. The unit must be listed by a national listing organization (the rule does not name NSF/ANSI 41), and remaining wastewater still needs an interceptor and a trench or bed dispersal system unless graywater is reused under the graywater rules (Ariz. Admin. Code R18-9-E303). A 2024 bill (HB2097) to exempt homes with all-composting toilets from septic requirements failed in the Senate on June 12, 2024.

Electrical code (off-grid solar and wiring) Local adoption

Arizona does not adopt the NEC at the state level; each city or county adopts and amends its own edition, and contractors are licensed by the Registrar of Contractors. No statewide solar or off-grid rule was found. NFPA's enforcement map (as of August 3, 2026) lists: Local adoption only.

Checked 2026-11-02. Back to the table

Arkansas

Rainwater collection Allowed, limits

State law requires the State Board of Health to allow harvested rainwater systems for non-potable use if the system is designed by an Arkansas-licensed professional engineer, has cross-connection safeguards, and complies with the state plumbing code (Ark. Code Ann. § 17-38-201(g)).

Arkansas Department of Health, Plumbing Law 2022 (Ark. Code Ann. § 17-38-201)

Greywater reuse No state rule

No Arkansas rule allowing graywater reuse was found. Under the Department of Health's onsite wastewater rules, household wastewater other than toilet waste must be treated or disposed of through an approved onsite system (Rules Pertaining to Onsite Wastewater, Section 9.10.3). Check with the Arkansas Department of Health.

Arkansas Department of Health, Rules Pertaining to Onsite Wastewater (effective Sept. 5, 2024)

Composting toilets Allowed, limits

Only pre-manufactured composting or incinerating toilets authorized by the Department of Health may be used, and they must be evaluated under NSF Standard 41 by an ANSI-approved laboratory. All other wastewater from the house must still be treated under the onsite rules, and stabilized compost must be buried on site or taken to an approved landfill (Rules Pertaining to Onsite Wastewater, Section 9.10, effective Sept. 5, 2024).

Arkansas Department of Health, Rules Pertaining to Onsite Wastewater

Electrical code (off-grid solar and wiring) NEC 2020

IAEI lists the 2020 NEC with Arkansas amendments, effective August 1, 2022, adopted through the Arkansas Department of Labor as the minimum standard; local jurisdictions may adopt stricter codes. Secondary source; no statewide solar or off-grid rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2020 with AR amendments (8/1/2022); 2026 update underway.

Checked 2026-11-02. Back to the table

California

Rainwater collection Allowed

The Rainwater Capture Act of 2012 (AB 1750; Water Code §§ 10570–10574) says using rainwater collected from rooftops does not require a state water right permit. Rain barrel systems are for outdoor non-potable use on the landowner's own property.

AB 1750 (2012) bill text, as amended Aug. 24, 2012 (leginfo.ca.gov)

Greywater reuse Allowed, limits

Under Chapter 15 of the California Plumbing Code, a clothes washer ('laundry-to-landscape') system at a one- or two-family home needs no construction permit if it meets about 13 conditions. These include irrigation only on the same property, no pump other than the washer's own, discharge under at least 2 inches of mulch or soil, no ponding or runoff, and a diverter to the sewer. Other graywater systems need a permit from the local building department.

Composting toilets No state rule

No statewide California statute or code section specifically authorizing composting toilets for homes was confirmed. Approval is handled by county environmental health and building departments; for example, Sonoma County's local manual requires NSF 41 units but cannot take effect until the county code stops requiring water-flush toilets in every dwelling. Check with your county environmental health department.

Permit Sonoma, OWTS Manual Section 21: Waterless Toilets (local example)

Electrical code (off-grid solar and wiring) NEC 2023

The 2025 California Electrical Code (Title 24, Part 3), based on the 2023 NEC, took effect statewide on January 1, 2026. It is adopted by the California Building Standards Commission and enforced locally by the building official; local amendments need a climatic, geologic or topographic justification. Secondary source; no off-grid-specific statewide rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2023 with CA amendments (1/1/2026).

Checked 2026-11-02. Back to the table

Colorado

Rainwater collection Allowed, limits

Single-family homes and multi-family buildings with four or fewer units may collect rooftop runoff in up to two rain barrels totaling 110 gallons, with no permit. The water may be used only outdoors on the same property (e.g., lawn and garden irrigation), not for drinking or indoor use (C.R.S. § 37-96.5-103, from HB16-1005). Homes on qualifying exempt wells can get a broader rooftop collection permit (C.R.S. §§ 37-92-602(1)(g), 37-90-105(1)(f)).

Colorado Division of Water Resources, Rainwater, Storm Water & Graywater

Greywater reuse Permit needed

Under CDPHE Regulation 86 (effective June 30, 2015), graywater is allowed only where a city or county has adopted a local graywater control program. Single-family homes may use it for subsurface irrigation and indoor toilet flushing, up to 400 gallons per day combined; agricultural irrigation is prohibited. Use must also comply with water rights and well permit limits.

Composting toilets Allowed, limits

Composting toilets are allowed under the state onsite wastewater rule (CDPHE Regulation 43, 5 CCR 1002-43), which local health agencies enforce. Delta County's guidance says a permanent dwelling needs a manufactured unit meeting NSF Standard 41 and still needs a full-size permitted septic system (OWTS) for graywater, with no size reduction.

Electrical code (off-grid solar and wiring) NEC 2023

The Colorado State Electrical Board adopted the 2023 NEC effective August 1, 2023. Local jurisdictions have up to a year to adopt the newest state-adopted edition, and local inspectors must meet state inspector qualifications. Secondary source; no statewide off-grid rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2026 (8/1/2026).

Checked 2026-11-02. Back to the table

Connecticut

Rainwater collection No state rule

No Connecticut statute or rule restricting residential rainwater collection was found; the 2015 PNNL survey lists Connecticut as having no rainwater harvesting regulations. Check with your local health or building department.

PNNL-24347, Rainwater Harvesting: State Regulations and Technical Resources (2015), secondary

Greywater reuse Restricted

Under the Public Health Code, graywater from residential sinks, tubs, showers and laundry (with no flush toilets connected) must go to a septic tank and leaching system at least half the size of the normally required system (Conn. Agencies Regs. § 19-13-B103d(f)). No provision allowing graywater reuse was found. The Department of Public Health and local health directors administer the rule.

CT DPH, Technical Standards for Subsurface Sewage Disposal Systems (2023 master, incl. Public Health Code 19-13-B103)

Composting toilets Permit needed

The local director of health may approve a large-capacity or heat-assisted composting toilet: to replace a privy or failing system, or at a single-family home only if the lot is tested and found suitable for a standard subsurface system (Conn. Agencies Regs. § 19-13-B103f). The rule does not mention NSF/ANSI 41, and graywater still goes to a half-size septic and leaching system.

Electrical code (off-grid solar and wiring) NEC 2020

IAEI lists the 2020 NEC with Connecticut amendments, effective October 1, 2022, as part of the State Building Code (Office of the State Building Inspector); local building officials or licensed electrical inspectors do inspections. Secondary, undated source; a newer edition was not confirmed. No statewide off-grid rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2020 with CT amendments (10/1/2022); 2023 update underway.

Checked 2026-11-02. Back to the table

Delaware

Rainwater collection No state rule

No Delaware statute or rule restricting residential rainwater collection was found; the 2015 PNNL survey lists Delaware as having no rainwater harvesting regulations. Check with your county.

PNNL-24347, Rainwater Harvesting: State Regulations and Technical Resources (2015), secondary

Greywater reuse Permit needed

DNREC's onsite wastewater regulations define greywater as untreated wastewater that has not contacted toilet waste (excluding kitchen sinks and dishwashers). They encourage greywater collection and use, but any such system is subject to DNREC review and approval (7 DE Admin. Code 7101, Section 3.28).

7 DE Admin. Code 7101, On-Site Wastewater Treatment and Disposal Systems (DNREC)

Composting toilets No state rule

No composting-toilet provision was found in DNREC's onsite wastewater regulations (7 DE Admin. Code 7101); NSF/ANSI 41 requirements were not confirmed. Contact DNREC's Ground Water Discharges Section.

7 DE Admin. Code 7101 (DNREC)

Electrical code (off-grid solar and wiring) NEC 2023

IAEI lists the 2023 NEC, effective January 1, 2026, enacted by the Delaware Fire Prevention Commission / State Fire Marshal; local jurisdictions must adopt the NEC edition the Commission enacts. Secondary source; no statewide off-grid rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (1/1/2026).

Checked 2026-11-02. Back to the table

Florida

Rainwater collection No state rule

No Florida statute or rule restricting residential rainwater collection was found; the 2015 PNNL survey lists none and suggests checking the county for local incentives.

PNNL-24347, Rainwater Harvesting: State Regulations and Technical Resources (2015), secondary

Greywater reuse Permit needed

Florida law treats graywater (bath, lavatory, laundry and non-kitchen sink waste) as part of domestic sewage. A graywater tank counts as part of an onsite sewage system, which needs a permit to build or operate, and the department must approve individual graywater disposal systems where blackwater goes to a central sewer (s. 381.0065, F.S.). The onsite program is moving in phases from the Department of Health to the Department of Environmental Protection (ch. 2024-180).

Section 381.0065, Florida Statutes (2024) (Florida Senate)

Composting toilets Allowed, limits

Waterless, incinerating and composting toilets may be approved if they meet ANSI/NSF 41-2018 (or NSF P157-2019 for incinerating units). Graywater and other wastewater must still be properly disposed of, and toilet liquids must be plumbed into the onsite system. When these toilets are used exclusively, the home's drainfield is reduced by 25% (Fla. Admin. Code R. 62-6.009(1)).

Fla. Admin. Code R. 62-6.009, Alternative Systems (Cornell LII)

Electrical code (off-grid solar and wiring) NEC 2020

The statewide Florida Building Code, 8th Edition (2023), uses the 2020 NEC, effective December 31, 2023. The 9th Edition (2026), which references the 2023 NEC (NFPA 70), takes effect December 31, 2026. No statewide off-grid rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2020 (12/31/2023); 2023 update underway.

Checked 2026-11-02. Back to the table

Georgia

Rainwater collection Allowed, limits

Georgia's State Minimum Standard Plumbing Code includes a rainwater harvesting chapter (Chapter 15, based on the 2012 IPC). It allows roof rainwater for toilet and urinal flushing, clothes washing and cooling tower makeup, with filtration and disinfection required. Systems under 200 gallons used outdoors normally need no disinfection.

U.S. EPA REUSExplorer, Georgia rainwater collected onsite for non-potable reuse (secondary)

Greywater reuse Allowed, limits

Georgia's 2009 Gray Water Recycling Systems Guidelines (Georgia DNR/EPD) cover graywater from lavatories, tubs, showers and clothes washers for toilet flushing and subsurface irrigation, with treatment that includes filtration, disinfection and dye. They are guidelines rather than a statute. Permitting requirements were not confirmed; check with the local building department.

Composting toilets No state rule

The Department of Public Health's onsite sewage rules (Ga. Comp. R. & Regs. 511-3-1) exclude composting toilets from the definition of a privy. Alternative systems must be on the Department's approved list and meet the onsite sewage manual, but no composting-toilet or NSF/ANSI 41 provision was confirmed. Check with your county board of health.

Electrical code (off-grid solar and wiring) NEC 2023

Georgia adopted the 2023 NEC with no amendments, effective January 1, 2025, through the Department of Community Affairs' Codes Advisory Board. Secondary source; enforcement scope not stated. No statewide off-grid rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (1/1/2025).

Checked 2026-11-02. Back to the table

Hawaii

Rainwater collection Allowed

The Department of Health says rainwater catchment systems on individual homes are not regulated by DOH. It recommends following the University of Hawaii CTAHR rainwater catchment guidelines, using certified filtration or treatment, and testing at a DOH-approved lab.

Hawaii DOH Safe Drinking Water Branch, Rain Catchment

Greywater reuse Allowed, limits

Act 233 (2013) amended HRS § 342D-70 so DOH may authorize counties to run graywater recycling programs for irrigating lawns and gardens. Those programs must follow the state plumbing code and have a DOH-approved plan. DOH's 2009 graywater guidelines allow subsurface irrigation on the property where the graywater is generated.

Composting toilets Allowed, limits

Since Act 239 (effective July 12, 2016), HRS § 27-21.6 requires counties to approve the installation and use of composting toilets in areas that municipal wastewater systems cannot reach. NSF/ANSI 41 requirements and whether a separate graywater system is required were not confirmed; check with your county and DOH's Wastewater Branch.

Hawaii Session Laws 2016, Act 239 (SB 2583)

Electrical code (off-grid solar and wiring) NEC 2020

IAEI lists the 2020 NEC, effective March 15, 2022, listed under the Hawaii Building Codes Commission; county adoption and enforcement were not confirmed. Secondary, undated source; no statewide off-grid rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2020 (3/14/2023).

Checked 2026-11-02. Back to the table

Idaho

Rainwater collection Allowed

No statute specific to rooftop rainwater harvesting was found. Idaho Department of Water Resources guidance treats precipitation and snowmelt runoff captured before it reaches a natural stream as 'diffused surface water' that is not public water, so no water right permit is required to capture and use it; a use that significantly reduces water feeding a natural watercourse may injure senior water-right holders.

IDWR Administrator's Memorandum, Application Processing No. 67 (Feb. 28, 2003)

Greywater reuse Permit needed

Idaho's Individual/Subsurface Sewage Disposal Rules (IDAPA 58.01.03, Dept. of Environmental Quality) cover gray water (defined by reference to IDAPA 58.01.16) and require a valid installation permit before any individual or subsurface sewage disposal system is installed, modified or expanded. Specific gray-water reuse allowances were not confirmed; check with DEQ or your local health district.

IDAPA 58.01.03, Individual/Subsurface Sewage Disposal Rules (secs. 003.16, 005.01)

Composting toilets Allowed, limits

IDAPA 58.01.03 lists composting toilets, incinerators and vault toilets as proprietary non-discharging systems that may be used only if the design is approved by the DEQ Director. An NSF/ANSI 41 requirement was not found in the rule, and property owners must still connect all plumbing fixtures that discharge wastewater to an approved wastewater system.

IDAPA 58.01.03 (secs. 001.03.a.ii, 009.01.c)

Electrical code (off-grid solar and wiring) NEC 2023

The Idaho Division of Occupational and Professional Licenses (DOPL) moved to the 2023 NEC on April 19, 2024, with exceptions set by temporary rules; permits pulled before that date are inspected under the 2017 NEC, and full enforcement began no later than January 1, 2025. No statewide solar/off-grid-specific rule confirmed. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (7/1/2023) with ID amendments.

Checked 2026-11-02. Back to the table

Illinois

Rainwater collection No state rule

No statewide limit on collecting rainwater was found. Rainwater harvesting distribution systems are treated as plumbing for non-potable use only and must meet the Illinois Plumbing Code (77 Ill. Adm. Code 890, Illinois Dept. of Public Health), which defines rainwater as precipitation collected from roofs or other manmade above-ground surfaces; enactment status of the 2011 amending bill was not independently confirmed.

Greywater reuse No state rule

A permitted statewide graywater reuse path was not confirmed. IDPH's 2019 proposed Plumbing Code amendments define graywater and list a section for on-site collected graywater, but adoption of that section was not confirmed; the Private Sewage Disposal Code requires domestic wastes other than toilet waste to go to a conventional private sewage system. Check with your county health department.

Composting toilets Allowed, limits

Compost toilets are allowed under the Private Sewage Disposal Code but must comply with NSF/ANSI Standard 41 and bear the NSF or approved certification seal, be sized per the manufacturer and maintained by the owner. Other domestic wastes (e.g., sink, shower, laundry water) must still go to a conventional private sewage disposal system.

77 Ill. Adm. Code 905.130, Human Waste Disposal (IDPH)

Electrical code (off-grid solar and wiring) Local adoption

Illinois has no statewide electrical code for general construction; adoption and enforcement are local. IAEI lists the 2008 NEC adopted by the Capital Development Board (effective July 1, 2011) for state work only, and electricians are not licensed statewide. NFPA's enforcement map (as of August 3, 2026) lists: 2008 (7/1/2011), commercial occupancies outside local jurisdictions with adoption authority.

Checked 2026-11-02. Back to the table

Indiana

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Indiana as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Restricted

Indiana Department of Health guidance says wastewater from bathing, laundry and dishwashing must still be collected, treated and disposed of through an on-site sewage system under 410 IAC 6-8.3, administered by local health departments. No separate statewide graywater reuse allowance was found.

Indiana Dept. of Health, Composting and Incinerating Toilets Guidance (rev. Nov. 19, 2012)

Composting toilets Allowed, limits

The local health officer may allow a composting or incinerating toilet in a single-family dwelling; it should be certified to NSF/ANSI Standard 41. It is not a substitute for an on-site sewage system, which is still required under 410 IAC 6-8.3; commercial facilities are reviewed case by case by the state health department.

Indiana Dept. of Health, Composting and Incinerating Toilets Guidance (rev. Nov. 19, 2012)

Electrical code (off-grid solar and wiring) NEC 2008

The statewide Indiana Electrical Code (675 IAC 17-1.8, 2009 Edition) is based on the 2008 NEC for commercial work; IAEI lists the 2017 NEC for one- and two-family residential work (effective Dec. 26, 2019). Local jurisdictions may not adopt their own electrical code without Fire Prevention and Building Safety Commission approval. A draft rule adopting the 2023 NEC as the Indiana Electrical Code, 2026 Edition was found, but its effective date was not confirmed. NFPA's enforcement map (as of August 3, 2026) lists: 2008 commercial with IN amendments (8/26/2009); 2017 (2018 IRC) one- and two-family dwellings (12/26/2019); 2023 update underway.

Checked 2026-11-02. Back to the table

Iowa

Rainwater collection No state rule

No statewide rainwater harvesting statute was found. The state plumbing code (641 IAC 25) adopts chapters 2 to 17 of the 2021 Uniform Plumbing Code with Iowa amendments; how Iowa treats the UPC's rainwater catchment provisions was not confirmed. Roof drains may not discharge into septic tanks or soil absorption systems.

Greywater reuse No state rule

Iowa's private sewage disposal rules (567 IAC 69) do not separately address gray water; discharging any wastewater from private sewage disposal systems except as permitted in the chapter is prohibited, and construction permits come from the DNR or the county board of health. Check with your county board of health.

567 IAC 69 (rules 69.1(2), 69.1(4), 69.1(8))

Composting toilets No state rule

The current private sewage disposal rules (567 IAC 69) address vault and portable toilets but no composting-toilet provision was found. Check with your county board of health, which is an administrative authority under the chapter.

567 IAC 69, Private Sewage Disposal Systems

Electrical code (off-grid solar and wiring) NEC 2023

IAEI lists the 2023 NEC with Iowa amendments, effective July 1, 2025, published by the State Fire Marshal Division's Building Code Bureau, which employs state electrical inspectors. The split between state and local enforcement was not confirmed. NFPA's enforcement map (as of August 3, 2026) lists: 2023 with IA amendments (7/1/2025); 2026 update underway.

Checked 2026-11-02. Back to the table

Kansas

Rainwater collection No state rule

No statewide rainwater harvesting rule was found. Kansas requires a water right for most water use but exempts water used solely for domestic purposes (household, livestock on pasture, and up to two acres of lawn and garden); the Division of Water Resources does not address rainwater collection on its water law page.

Kansas Dept. of Agriculture, Division of Water Resources: Why Do I Need a Water Right?

Greywater reuse Restricted

KDHE Bulletin 4-2 (March 1997) defines domestic wastewater to include kitchen, laundry, shower and bath water and requires all domestic wastewater to go to an approved sewer, lagoon, septic or alternative system. Alternative systems can be approved through a local variance or, where no local code exists, through KDHE; county sanitary codes generally govern.

KDHE Bulletin 4-2, Minimum Standards for Design and Construction of Onsite Wastewater Systems

Composting toilets No state rule

KDHE's minimum onsite standards do not mention composting toilets, and all domestic wastewater must still go to an approved system. Check with your county health or environmental office.

KDHE Bulletin 4-2

Electrical code (off-grid solar and wiring) Local adoption

Kansas has no statewide electrical code for general use; adoption is local. The 2008 NEC applies to state-owned buildings (effective Feb. 4, 2011), and electricians are not licensed statewide. NFPA's enforcement map (as of August 3, 2026) lists: 2008 (2/4/2011, State Fire Marshal).

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Kentucky

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Kentucky as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Permit needed

Kentucky's onsite sewage rule (902 KAR 10:085) defines greywater (laundry, lavatory, shower, tub; not kitchen sinks) and provides for residential greywater waste systems; a septic tank is not required for a greywater system, and design flow for the main system can be reduced when greywater is separated. Permits are issued only by certified inspectors before construction, under the Cabinet for Health and Family Services. Text reviewed was the pre-engrossed version.

902 KAR 10:085, Kentucky on-site sewage disposal systems (secs. 1(17), 2(1), 6(1), 6(15))

Composting toilets Allowed, limits

902 KAR 10:085 recognizes approved permanent nonwater-carriage toilets such as composting and incinerator toilets, allowing a reduced design flow for the onsite system when they are used exclusively in a residence; an onsite system is still needed for other wastewater. An NSF/ANSI 41 requirement was not found in the text reviewed.

902 KAR 10:085 (secs. 4(4), 6(1))

Electrical code (off-grid solar and wiring) NEC 2023

IAEI lists the 2023 NEC, effective January 1, 2025, with the Department of Housing, Buildings and Construction as the state contact. State vs. local enforcement split not confirmed. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (1/1/2025); 2026 update underway.

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Louisiana

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Louisiana as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse No state rule

The State Sanitary Code does not use the term gray water in the sections reviewed; devices that recycle or reuse household wastewater are treated as proprietary devices that only the state health officer can approve, with a permit before installation. Check with the Louisiana Department of Health.

LAC 51:XIII-713, Other Individual Sewerage Systems

Composting toilets Permit needed

Composting units are listed among proprietary devices that may be used only with approval of the state health officer and a permit issued before installation. Homes without pressurized water must use a pit privy or other non-water-borne system for excreta. An NSF/ANSI 41 requirement was not found.

Electrical code (off-grid solar and wiring) NEC 2020

IAEI lists the 2020 NEC, effective January 1, 2023, with the Louisiana State Uniform Construction Code Council as contact; electricians are not licensed statewide and local jurisdictions may add requirements. Whether a newer edition has since been adopted was not confirmed. NFPA's enforcement map (as of August 3, 2026) lists: 2020 (1/1/2023).

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Maine

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Maine as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Permit needed

Under the Subsurface Wastewater Disposal Rules (10-144 CMR 241, Maine CDC; current rule effective Sept. 23, 2023), the Local Plumbing Inspector may approve a grey wastewater disposal field for single-family homes with pressurized water, sized at the greater of 126 gpd or 70% of base design flow (laundry-only: 55 gpd or 20%). Homes with hand-carried or hand-pumped water and up to three grey fixtures may use a primitive disposal field (25 gpd design flow, no septic tank), which requires an alternative toilet.

Composting toilets Permit needed

Permits are required for all alternative toilet installations except portable units; only non-discharging, non-water-carriage toilets that treat or stabilize waste may be approved for permanent use, and composting toilet liquid overflow must go to a primitive or conventional disposal field. An approved disposal field is still required unless no grey wastewater is generated. NSF/ANSI 41 is not mentioned in the text reviewed.

10-144 CMR 241, Section 5 (subsections M, N, Q)

Electrical code (off-grid solar and wiring) NEC 2023

IAEI lists the 2023 NEC, effective July 1, 2024; electrician licensing is through the Electricians' Examining Board. State vs. local enforcement split not confirmed. NFPA's enforcement map (as of August 3, 2026) lists: 2026 with ME amendments (7/1/2026).

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Maryland

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Maryland as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Restricted

2018 legislation (SB 496) defines graywater as bath, shower and lavatory sink water, with uses ranging from outdoor subsurface irrigation to indoor toilet flushing depending on treatment level, and local governments to authorize installations. As of the MDE page fetched, the Maryland Department of the Environment was still developing the implementing regulations, so no effective date was confirmed.

Maryland Department of the Environment: Graywater

Composting toilets Permit needed

MDE issues a General Permit for the Discharge of Composting Toilet Wastewater to Groundwater by Land Application (No. 23-CT, renewal effective Sept. 1, 2026; existing 18-CT permittees must file a Notice of Intent by Feb. 28, 2027). Whether NSF/ANSI 41 is required and whether a septic system is still required were not confirmed.

MDE General Permit 23-CT, Composting Toilet Wastewater

Electrical code (off-grid solar and wiring) NEC 2023

IAEI lists the 2023 NEC, effective March 1, 2025, with the Office of the State Fire Marshal as contact. State vs. local enforcement split not confirmed. NFPA's enforcement map (as of August 3, 2026) lists: 2020 (7/1/2025) with MD amendments; 2023 update underway.

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Massachusetts

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Massachusetts as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Permit needed

Title 5 (310 CMR 15.262) allows residential, commercial and public facilities to discharge greywater to an on-site system when that system receives only greywater; residential soil absorption area may be reduced up to 50% for new construction or upgrades. Homes need a Disposal System Construction Permit and Certificate of Compliance from the local Board of Health; MassDEP approves commercial/public reuse.

Composting toilets Allowed, limits

Humus/composting toilets are certified for general use under 310 CMR 15.289, including residential new construction where a fully compliant Title 5 system could otherwise be installed. If greywater is generated, a septic tank (or approved filter) and soil absorption system are still required. NSF/ANSI 41 is not mentioned in the text reviewed; plumbing approval and local Board of Health permits apply.

Electrical code (off-grid solar and wiring) NEC 2023

IAEI lists the 2023 NEC, effective February 17, 2023, with the Department of Fire Services among state contacts. Enforcement details not confirmed. NFPA's enforcement map (as of August 3, 2026) lists: 2026 with MA amendments (4/24/2026).

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Michigan

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Michigan as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Permit needed

State law (MCL 333.12751 and 333.12757) allows an 'acceptable alternative greywater system' approved for use by the local health department; installation and use are regulated and may be inspected annually by the local health department. Separate statewide no-permit greywater reuse was not found.

Composting toilets Permit needed

Compost toilets are named as an 'acceptable innovative or alternative waste treatment system' that must be approved for use by the local health department; the state health department sets guidelines after consulting the state plumbing board. The statute does not reference NSF/ANSI 41. An owner using such a system together with an acceptable alternative greywater system is not required to connect to an available public sewer (with fee exceptions).

Electrical code (off-grid solar and wiring) NEC 2023

Michigan Electrical Code (Part 8 rules, R 408.30801) adopts the 2023 NEC, effective March 12, 2024. The 2021 Michigan Residential Code, effective August 29, 2025, rescinded its duplicate NEC rules and references the Michigan Electrical Code directly. The code is administered and enforced by the local authority having jurisdiction designated by the governing body (Rule 810); LARA's Bureau of Construction Codes writes the rules. A new Part 8 rule set (2026-17 LR) was still a proposed draft as of fall 2026. No statewide solar or stand-alone system amendment was found in the Part 8 rules. NFPA's enforcement map (as of August 3, 2026) lists: 2023 commercial (3/12/2024); 2014 one- and two-family dwellings (2/8/2016); 2026 update underway.

Checked 2026-11-02. Back to the table

Minnesota

Rainwater collection Permit needed

Under the Minnesota Plumbing Code (Minn. R. 4714.1602), nonpotable rainwater catchment systems that supply uses such as toilets and urinals need plumbing plans approved by the state before a permit is issued. The rule does not mention outdoor-only rain barrels, and no other statewide limit on collection was found.

Greywater reuse Allowed, limits

MPCA rules (Minn. R. 7080.2240) treat a gray water system as a subsurface system that takes no toilet waste, is sized at 60% of normal sewage flow, and uses a septic tank of at least 750 gallons for 3 or fewer bedrooms. Products used must be approved by the local unit of government (7080.1050). A no-permit greywater reuse allowance was not found.

Composting toilets Allowed, limits

Minnesota rules define 'toilet waste treatment devices' to include composting, incinerating and other waterless toilets (Minn. R. 7080.1100, subp. 86), and a privy may employ a toilet treatment device (7080.2280). The rules read do not cite NSF/ANSI 41. Gray water from the home still goes to a system meeting 7080.2240, which bars toilet waste. MPCA writes the rules; local units of government administer them.

Electrical code (off-grid solar and wiring) NEC 2026

The Minnesota Board of Electricity adopted the 2026 NEC (Minn. R. ch. 1315), effective August 17, 2026: permits filed on or after that date use the 2026 NEC, and earlier permits use the 2023 NEC. The DLI page does not describe how enforcement is split between the state and local jurisdictions, and lists no statewide solar or off-grid amendment. NFPA's enforcement map (as of August 3, 2026) lists: 2026 (8/17/2026).

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Mississippi

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Mississippi as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse No state rule

No greywater-specific provision was found in the part of the Mississippi State Department of Health onsite wastewater regulations that was reviewed. Systems take residential waste, and alternative wastewater technology must be reviewed and approved by MSDH's Division of On-Site Wastewater. Check with your county health department.

Composting toilets Allowed, limits

MSDH onsite wastewater regulations list 'non-water borne' systems as a disposal option (Rule 1.5.6) and treatment product (Rule 2.1.5). The product needs third-party certification that it passed testing and listing (Rule 2.1.9), though the standard is not named in the portion read. Whether a separate system is still required for the house was not confirmed.

MSDH On-Site Wastewater Regulations (Part 18, Subpart 77)

Electrical code (off-grid solar and wiring) Local adoption

No statewide NEC adoption was found. A national compiler lists Mississippi as 'Local', noting that the City of Biloxi adopted the 2026 NEC effective June 1, 2026. Check with your local building department. No official state source was found. NFPA's enforcement map (as of August 3, 2026) lists: Local incorporation by reference only.

Checked 2026-11-02. Back to the table

Missouri

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Missouri as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Allowed, limits

19 CSR 20-3.060 defines gray water as bath, laundry and floor-drain waste, not toilet or kitchen waste. When waterless toilets are used, design flow for gray water systems may be cut by up to 40%, decided case by case. DHSS regulates onsite systems of 3,000 gallons per day or less, and local ordinances may apply instead (19 CSR 20-3.050). A no-permit greywater reuse allowance was not found.

Composting toilets Allowed, limits

Missouri rules list composting and incinerating toilets as examples of a 'non-ground absorption sewage disposal system' (19 CSR 20-3.060(1)(A)32). Where there are no flush toilets, a privy, chemical toilet or other toilet device must be built and kept in a manner the Department of Health approves (19 CSR 20-3.040(7)(B)). The rules cite NSF Standard 40 for aeration units but not NSF/ANSI 41. Gray water still goes to a gray water system.

Electrical code (off-grid solar and wiring) Local adoption

No statewide NEC adoption was found. A national compiler lists Missouri as 'Local'. Check with your local building department. No official state source was found. NFPA's enforcement map (as of August 3, 2026) lists: Local incorporation by reference only.

Checked 2026-11-02. Back to the table

Montana

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Montana as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Permit needed

Indoor reuse such as toilet flushing needs no review if the gray water ends up in a compliant wastewater system. Irrigation needs a local health department permit and must be subsurface under DEQ-4. Other limits: no food crops except fruit and nut trees, at least 4 ft of natural soil above a limiting layer, and 100 ft from wells and surface water unless waived. Kitchen water qualifies only with a waste segregation system (ARM 17.36.319 and 17.36.919; MCA 75-5-326).

Composting toilets Allowed, limits

Montana DEQ rules recognize a 'waste segregation system': dry disposal of toilet waste by composting, chemical, dehydrating or incinerator treatment, paired with a separate disposal method for gray water. Gray water must still be treated and disposed of through a wastewater system that meets DEQ rules. The rules read do not mention NSF/ANSI 41.

Electrical code (off-grid solar and wiring) NEC 2023

The Montana Building Codes Bureau lists the 2023 NEC, effective September 26, 2026, amended by ARM Title 24, Chapter 301. A national compiler lists the prior edition as 2020 (effective June 10, 2022). Electrical permits are issued by the state program and by certified city, county and town programs. No statewide solar or off-grid rule was listed. NFPA's enforcement map (as of August 3, 2026) lists: 2020 with MT amendments (6/10/2022); 2023 update underway (projected 9/2026).

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Nebraska

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Nebraska as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Restricted

Under Title 124, graywater counts as wastewater, and a dwelling that makes wastewater must have an onsite wastewater treatment system permitted by NDEE before construction. Systems must also be registered. University of Nebraska Extension notes that discharging untreated graywater is not legal; reuse needs treatment, an engineer's design and an NDEE permit, with plumbing that keeps graywater separate from blackwater.

Composting toilets No state rule

No Title 124 provision on composting toilets or NSF/ANSI 41 was found in the portion reviewed. Graywater from the home is wastewater and still requires a permitted onsite system. Check with NDEE's Onsite Wastewater Program.

NDEE Title 124 Onsite Wastewater Treatment Systems

Electrical code (off-grid solar and wiring) NEC 2023

The Nebraska State Electrical Division adopted the 2023 NEC beginning August 1, 2024. By statute (Neb. Rev. Stat. 81-2104), the 2017 edition still applies to sections 210.8(A), 210.8(A)(3), 210.8(A)(5), 230.67(A) and 230.85. The State Electrical Board enforces the code, and municipal and county inspection programs also exist. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (8/1/2024); 2026 update underway.

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Nevada

Rainwater collection Allowed, limits

NRS 533.027 exempts from state water-rights law the collection of precipitation from the rooftop of a single-family dwelling for nonpotable domestic use.

NRS 533.027 (Nevada Legislature)

Greywater reuse Permit needed

Graywater may be used only for underground irrigation at a single-family dwelling, on the same lot, and the homeowner must first get a permit to build the system (NAC 444.837). A holding tank is required, and the soil must not perc slower than 120 minutes per inch. The state Division of Public and Behavioral Health issues permits through its local offices; some counties have their own health districts.

Composting toilets No state rule

No Nevada rule on composting toilets or NSF/ANSI 41 was confirmed. NAC 444.818 requires every dwelling to have an approved method of sewage disposal through an approved individual sewage disposal system. NAC 444.7654 defines 'nonsewered toilet', but its text was not reviewed. Check with your county health department or DPBH.

Electrical code (off-grid solar and wiring) Local adoption

Under NRS 278.583, construction must meet the NEC in the form most recently approved by the city or county governing body. A new edition is automatically approved unless the local body rejects it within 60 days of publication, and local changes may not lower its standards. A national compiler lists Nevada at the 2017 NEC (July 1, 2018), with local jurisdictions free to be stricter. Check with your local building department. NFPA's enforcement map (as of August 3, 2026) lists: 2017 (7/1/2018, Nevada State Public Works Division).

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New Hampshire

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists New Hampshire as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Restricted

NHDES rules allow a gray water 'mini-dry well' only for a structure with no running water and no other wastewater discharge, set at least 75 ft from drinking water wells and surface waters (Env-Wq 1022.02). Otherwise wastewater goes to an individual sewage disposal system approved by NHDES. The posted version of Env-Wq 1022.02 was set to expire October 1, 2026, and readoption of Env-Wq 1000 was under way in 2026.

Composting toilets Allowed, limits

NHDES rules exclude a 'privy or dry toilet' from the definition of an individual sewage disposal system (Env-Wq 1002.40). Privies must be 75 ft from wells, surface waters and abutting foundations, and the pit bottom must be 4 ft above seasonal high water (Env-Wq 1022.01). NSF/ANSI 41 was not confirmed. An NHDES fact sheet, SSB-8 'Alternatives to an Individual Sewage Disposal System', exists but could not be retrieved.

Electrical code (off-grid solar and wiring) NEC 2023

The state building code (RSA 155-A:1, as amended through 2025) includes the 2023 NEC and the 2021 IPC. Its latest amendments took effect July 1, 2025 and July 1, 2026. A state code list effective August 13, 2024 still showed the 2020 NEC, and the exact date the 2023 NEC took effect was not confirmed. Enforcement split between state and local was not confirmed. NFPA's enforcement map (as of August 3, 2026) lists: 2023 with NH amendments (7/1/2025).

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New Jersey

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists New Jersey as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Permit needed

Under N.J.A.C. 7:9A-7.5, a separate greywater system may be approved if it meets the state septic standards and the design shows an acceptable way to dispose of blackwater. When blackwater goes to its own subsurface system, both systems are designed for at least 75% of the normal sewage volume. Approval comes from the administrative authority (local health agency).

N.J.A.C. 7:9A-7.5

Composting toilets Restricted

Blackwater may go to a waterless toilet only if the applicant first gets a variance from the plumbing subcode (N.J.A.C. 5:23-3.15) before the greywater system is approved (N.J.A.C. 7:9A-7.5). Greywater still needs an approved system. NSF/ANSI 41 is not mentioned.

N.J.A.C. 7:9A-7.5

Electrical code (off-grid solar and wiring) NEC 2023

The Uniform Construction Code electrical subcode (N.J.A.C. 5:23-3.16) adopts the 2023 NEC with TIAs 1-13, with an adoption date of August 17, 2026. The plumbing subcode adopts the 2024 National Standard Plumbing Code. NJ DCA writes the rules. The DCA page does not mention a grace period or how enforcement is split. NFPA's enforcement map (as of August 3, 2026) lists: 2020 with NJ amendments (9/6/2022).

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New Mexico

Rainwater collection Allowed

The Office of the State Engineer says most homeowners can install and use a rainwater harvesting system, such as roof catchment and rain barrels, for landscape irrigation. Larger commercial projects should check with the OSE Water Rights Division and NMED. OSE's formal policy is on a separate page that was not reviewed.

NM Office of the State Engineer, Rainwater Harvesting

Greywater reuse Allowed, limits

Up to 250 gallons per day of residential gray water may be used without a permit for household gardening, composting or landscape irrigation, under the conditions in 20.7.3.810 NMAC. Kitchen sink, dishwasher and soiled-laundry water are excluded. Larger systems need an NMED permit (20.7.3.809 NMAC), may be used only for irrigation or toilet flushing, and may not irrigate food crops other than fruit and nut trees.

Composting toilets Allowed, limits

Composting and incinerating toilets must be installed under the New Mexico plumbing code and the local plumbing authority, and installing one does not reduce the property's design flow (20.7.3.803 NMAC). The on-site liquid waste system is therefore sized as if the toilet were not there. NSF/ANSI 41 is not mentioned. NMED's Liquid Waste Program administers the rules.

20.7.3.803 NMAC

Electrical code (off-grid solar and wiring) NEC 2020

The 2020 New Mexico Electrical Code (14.10.4 NMAC) adopts the 2020 NEC with amendments, effective March 28, 2023. It covers work under the jurisdiction of the Construction Industries Division. No solar, PV or stand-alone system amendments were found in the rule. NFPA's enforcement map (as of August 3, 2026) lists: 2020 (3/28/2023).

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New York

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists New York as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Restricted

Under 10 NYCRR Appendix 75-A.10, when a non-flush toilet is installed, wastewater from sinks, showers and other fixtures must still be treated; greywater systems are designed on a flow of 75 gallons per day per bedroom. No rule allowing untreated greywater reuse without a permit was found.

10 NYCRR Appendix 75-A.10 - Other systems (Cornell LII copy)

Composting toilets Allowed, limits

Composting toilets are allowed under 10 NYCRR Appendix 75-A.10 if they carry a label showing compliance with NSF Standard 41 (or equivalent), are installed per the manufacturer's instructions, and have a warranty of five years or more. Treatment of greywater from sinks, showers and other fixtures is still required.

10 NYCRR Appendix 75-A.10 - Other systems (Cornell LII copy)

Electrical code (off-grid solar and wiring) NEC 2023

The 2025 NYS Uniform Code took effect December 31, 2025; the national compiler IAEI lists New York on the 2023 NEC (listed effective 1/1/2026). The Uniform Code is administered and enforced by cities, towns and villages (in some cases counties), with the Department of State stepping in where both decline. New York City has its own electrical code. The state rule text checked did not itself name the NFPA 70 edition. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (12/31/2025).

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North Carolina

Rainwater collection Allowed

Session Law 2009-243 bars state, county or local building codes from prohibiting cisterns, and the NC Plumbing Code (Appendix C-1, later Chapter 13 nonpotable water systems) sets rules for rainwater used to flush toilets and urinals. A permit is required to build or alter an indoor nonpotable rainwater system; untreated rainwater may be used outdoors for irrigation and similar uses.

Greywater reuse Permit needed

G.S. 143-355.5 directs the state to identify acceptable gray water uses (such as toilet flushing and landscape irrigation), facilitate permitting and set standards with the Commission for Public Health. Under the onsite wastewater rules (15A NCAC 18E, effective January 1, 2024) household wastewater must go to an approved, permitted wastewater system; no permit-free greywater reuse allowance was found.

Composting toilets Permit needed

15A NCAC 18E lists composting toilets as a non-ground absorption system. Rule 18E .1001 allows alternative toilets (incinerating, composting, mechanical) that meet the NC Plumbing Code, but all other wastewater from the building must still go to an approved wastewater system; residuals must be removed by a permitted septage firm. An NSF/ANSI 41 requirement was not confirmed. Rules are published by the NC DHHS On-Site Water Protection Branch.

Electrical code (off-grid solar and wiring) NEC 2020

The current NC Electrical Code is the 2020 NEC with state amendments, effective November 1, 2021. The 2023 NEC with state amendments was approved in 2023-2024 but its January 1, 2025 start was put on indefinite delay by Session Law 2025-2 (HB 47), Section 5.12. The state lists a 2023 interpretation covering Articles 702, 705, 706 and 710 (standby, stand-alone systems, energy storage). NFPA's enforcement map (as of August 3, 2026) lists: 2020 with NC amendments (11/1/2021).

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North Dakota

Rainwater collection No state rule

No North Dakota rule specific to rainwater harvesting was found. The state's water permitting guide says a Department of Water Resources permit is needed for all uses of water unless the use is domestic, livestock, or fish/wildlife/recreation and under 12.5 acre-feet; it does not mention rainwater. Check with your county health department.

ND Department of Water Resources - Water permitting process

Greywater reuse No state rule

The state private sewage rules (NDAC 62-03.1-03) have no greywater-specific section; designs not described in the chapter may be submitted to the administrative authority (ND Department of Environmental Quality, district health units, or county/city health departments) for approval.

NDAC 62-03.1-03 Private Sewage Disposal Systems

Composting toilets No state rule

NDAC 62-03.1-03 does not specifically address composting toilets; chemical toilets and privies require approval from the administrative authority, and other system types may be submitted for approval. No NSF/ANSI 41 requirement was found. Check with your district or county health unit.

NDAC 62-03.1-03 Private Sewage Disposal Systems

Electrical code (off-grid solar and wiring) NEC 2023

The State Electrical Board's rule changes adopt the 2023 NEC (with the 2021 Life Safety Code); IAEI lists it effective July 1, 2024. The rule package also added smoke-alarm requirements for rooms in dwellings that contain energy storage systems. NFPA's enforcement map (as of August 3, 2026) lists: 2026 (7/1/2026).

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Ohio

Rainwater collection Permit needed

The Ohio Plumbing Code (OAC 4101:3-13-01, effective March 1, 2024) removes the model-code nonpotable water chapter and treats rainwater collection and onsite nonpotable reuse systems as private water systems regulated by the Ohio Department of Health under OAC Chapter 3701-28. A board of health permit is required to build or alter a private water system, and systems using a cistern need plans submitted to the board of health.

Greywater reuse Permit needed

OAC 3701-29-17 (effective January 1, 2015) sets four types of gray water recycling systems. Type 1 (up to 60 gallons per day, subsurface irrigation in the growing season) may be permitted by the local board of health; Types 2-4 (up to 1,000 gallons per day) need a permit under rule 3701-29-09. Gray water must stay on the property and systems need a diversion valve to the sewage system.

OAC 3701-29-17 Gray water recycling systems and alternative toilets

Composting toilets Allowed, limits

Composting toilets must be certified to NSF/ANSI 41 (or approved by the director of health) and are treated as sewage treatment system components. All other household wastewater (kitchen, laundry, bathing) must still go to a sewage treatment system, whose design flow may be reduced by up to 25 percent. Agency: Ohio Department of Health and local boards of health.

OAC 3701-29-17 Gray water recycling systems and alternative toilets

Electrical code (off-grid solar and wiring) NEC 2023

IAEI lists Ohio on the 2023 NEC, effective March 1, 2024 for commercial and April 15, 2024 for residential (with Ohio amendments). The Ohio Building Code electrical rule (OAC 4101:1-27-01) is effective March 1, 2024; the rule page itself did not name the edition. NFPA's enforcement map (as of August 3, 2026) lists: 2023 commercial (3/1/2024); residential with OH amendments (4/15/2024).

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Oklahoma

Rainwater collection Allowed

NCSL's 2025 rainwater map (built from U.S. DOE FEMP data) lists Oklahoma as a state that encourages rainwater harvesting or provides incentives for it. No statewide limit on household collection was found in this check; ask your county about any local rules before plumbing it indoors.

Greywater reuse Allowed, limits

Under 27A O.S. 2-6-107 and 2-6-108, private residential gray water (not kitchen sink or dishwasher water) may be used for household gardening, composting or landscape irrigation. No DEQ permit is needed for under 250 gallons per day if it is not sprayed, is outside a floodway, minimizes contact with people and pets and is not discharged to a waterway; above that a DEQ permit is required. OSU Extension notes systems are allowed only where the city has a gray water ordinance.

Composting toilets No state rule

No Oklahoma rule specific to composting toilets was confirmed. The DEQ says on-site sewage systems need an Authorization to Construct and alternative systems must be approved by DEQ before installation. NSF/ANSI 41 requirement not confirmed.

Oklahoma DEQ - On-site sewage treatment

Electrical code (off-grid solar and wiring) NEC 2023

IAEI lists Oklahoma on the 2023 NEC, effective September 14, 2024. An official state source was not checked this round. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (9/14/2024).

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Oregon

Rainwater collection Allowed

ORS 537.141(1)(h) exempts the collection and use of precipitation from an artificial impervious surface (such as a roof) from water right permit requirements.

ORS 537.141 (Oregon.public.law copy)

Greywater reuse Permit needed

A DEQ permit is required for any graywater reuse system (OAR 340-053). Tier 1 general permit: single-family homes and duplexes under 300 gallons per day of untreated/filtered graywater for subsurface irrigation of landscape plants or compost; Tier 2: under 1,200 gallons per day; Tier 3: individual permit. Systems must also connect to a permitted sewer or septic system.

Composting toilets Permit needed

Under OAR 918-770-0080, composting toilets listed to NSF Standard 41 are approved; other units need state Building Codes Division approval. A plumbing permit from the local authority is required, and residential installs are limited to sites where greywater goes to a DEQ-approved greywater system or public sewer.

Electrical code (off-grid solar and wiring) NEC 2026

The 2026 Oregon Electrical Specialty Code, based on the 2026 NEC with Oregon amendments, took effect October 1, 2026 (replacing the 2023 OESC), with some provisions phased in through 2027-2028. It keeps PV rapid-shutdown requirements for systems on buildings and adds rules for microgrid equipment. NFPA's enforcement map (as of August 3, 2026) lists: 2023 with OR amendments (10/1/2023); 2026 update underway (projected 10/1/2026).

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Pennsylvania

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Pennsylvania as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Permit needed

PA DEP classifies greywater systems as an alternate onlot sewage technology under 25 Pa. Code Chapter 73: greywater must still be treated by an onlot system, absorption area may be reduced up to 40 percent with a non-flush toilet, and the local sewage enforcement officer (SEO) issues the permit. No permit-free reuse allowance was found.

PA DEP - Greywater Systems alternate technology listing (2014)

Composting toilets Permit needed

25 Pa. Code 73.65 requires composting toilets to bear the NSF seal for Standard 41. For a new home, washwater and excess liquid must be treated by an onlot sewage system or other approved method, under one permit; an existing home needs no permit if its onlot system is not altered.

25 Pa. Code 73.65 (Cornell LII copy)

Electrical code (off-grid solar and wiring) NEC 2020

The Uniform Construction Code update approved October 16, 2025 took effect January 1, 2026; IAEI lists Pennsylvania on the 2020 NEC from that date. Over 90 percent of municipalities enforce the UCC locally; in opt-out municipalities L&I handles commercial work and certified third-party agencies handle residential. NFPA's enforcement map (as of August 3, 2026) lists: 2020 (1/1/2026).

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Rhode Island

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Rhode Island as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Restricted

RIDEM's OWTS rules (250-RICR-150-10-6) treat both blackwater and graywater as wastewater; a home with plumbing and no sewer must have a DEM-approved OWTS, and discharging treated or untreated wastewater to the ground surface requires the Director's approval. No graywater reuse allowance was found in the portion of the rules read.

250-RICR-150-10-6 OWTS Rules

Composting toilets Permit needed

The OWTS rules define compost toilets and include alternative toilets as OWTS components; installing or altering an OWTS needs RIDEM's written approval. The rules incorporate NSF/ANSI 41, but a direct requirement for composting toilets was not confirmed in the portion read.

250-RICR-150-10-6 OWTS Rules

Electrical code (off-grid solar and wiring) NEC 2023

IAEI lists Rhode Island on the 2023 NEC, effective December 31, 2025. An official state source was not checked this round. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (12/1/2025).

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South Carolina

Rainwater collection Allowed, limits

NCSL's 2025 rainwater map (built from U.S. DOE FEMP data) lists South Carolina as restricting rainwater collection and use: Collection from above-ground rooftop surfaces only. Potable use not allowed. We did not find the statute text itself in this check, so confirm details with your county health department or the state environmental agency.

Greywater reuse Permit needed

SC Regulation 61-56 recognizes gray water subsurface reuse systems (subsurface irrigation only, not indoor reuse); the owner must get a Department permit to construct and approval to operate, and only a registered professional engineer may design the system. Agency: SC Department of Environmental Services (DES).

SC DES - Regulation 61-56 Onsite Wastewater Systems

Composting toilets Permit needed

Appendix S of R.61-56 covers nonwater-carried systems (composting, incinerating): products must meet NSF/ANSI 41 or equivalent, plans from a SC-registered professional engineer are required, and where pressurized water produces gray water a separate permitted gray water system is required (initial size may be reduced 25 percent).

Electrical code (off-grid solar and wiring) NEC 2020

The 2020 NEC with SC modifications was adopted by the Building Codes Council on October 6, 2021, with local implementation January 1, 2023. Mandatory codes must be enforced by every municipality and county. NFPA's enforcement map (as of August 3, 2026) lists: 2020 with SC amendments (1/1/2023); 2023 adopted, effective 1/1/2027.

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South Dakota

Rainwater collection No state rule

No South Dakota rule specific to rainwater harvesting was found. DANR's water rights summary says most uses need a permit, but domestic farm, ranch and household use up to 25,920 gallons per day (18 gpm) is exempt; it does not mention rainwater.

SD DANR - Water Rights summary

Greywater reuse Allowed, limits

ARSD 74:53:01:38 sets graywater system design: minimum 25 gallons per person per day for homes and cabins, tanks built as septic tanks with three days' retention, and effluent may be reused for toilet flushing, sent to an absorption system, or used to irrigate lawns and non-food areas. Agency: SD Department of Agriculture and Natural Resources.

ARSD 74:53:01:38 Requirements for graywater system

Composting toilets Permit needed

ARSD 74:53:01:10 says composting, incinerator and chemical toilets are used where water or electricity is unavailable and are treated as experimental systems needing plans approved by the secretary before installation; 74:53:01:40 requires installation per manufacturer specs and a backup system for new technology. No NSF/ANSI 41 requirement was found.

Electrical code (off-grid solar and wiring) NEC 2023

ARSD 20:44:22:01 requires installations to conform to the NEC, defined in 20:44:14:01(11) as the 2023 edition (with tentative interim amendments 23-1 to 23-15), effective November 12, 2024. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (11/12/2024) with SD amendments.

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Tennessee

Rainwater collection Allowed, limits

NCSL's 2025 rainwater map (built from U.S. DOE FEMP data) lists Tennessee as restricting rainwater collection and use: Rainwater can be collected for domestic purposes as long as it is not for potable use. We did not find the statute text itself in this check, so confirm details with your county health department or the state environmental agency.

Greywater reuse No state rule

No statewide greywater-reuse rule was confirmed. Tennessee's subsurface sewage disposal rules (TDEC, Chapter 0400-48-01) govern household wastewater disposal; check with TDEC or your county health department.

TDEC - Regulations to Govern Subsurface Sewage Disposal Systems

Composting toilets Allowed, limits

Composting toilets must be certified to NSF Standard 41 before use (Rule 0400-48-01-.17). A composting toilet or pit privy is not allowed where running water is available unless there is an acceptable means of wastewater disposal; administered by TDEC's subsurface sewage disposal program.

Electrical code (off-grid solar and wiring) NEC 2017

Rule 0780-02-01-.02 adopts the 2017 NEC effective October 1, 2018, with state amendments (Section 110.24 available fault current optional; AFCIs optional in bathrooms, laundry areas, garages, unfinished basements and refrigeration circuits). Electrical inspection is under the State Fire Marshal's rules; the chapter also provides for local governments authorized to perform electrical inspections (0780-02-01-.20). No statewide solar/off-grid-specific rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2017 (10/1/2018) with TN amendments.

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Texas

Rainwater collection Allowed

Rainwater harvesting is legal and encouraged: Tax Code 151.355 exempts rainwater harvesting equipment from state sales tax, and Property Code 202.007 bars HOAs from banning rainwater harvesting installations. No statewide residential storage limit was found.

Texas Water Development Board - Rainwater Harvesting

Greywater reuse Allowed, limits

Residential graywater under 400 gallons per day (combined average) needs no TCEQ authorization if it meets 30 TAC 210.83: uses include foundation watering, gardening, composting, landscaping and toilet/urinal flushing; tanks labeled non-potable, purple pipe, backflow protection, no ground overflow, and overflow/diversion to a sewer or on-site sewage facility. Local permitting authorities may be stricter.

Composting toilets Permit needed

TCEQ's on-site sewage facility (OSSF) rules define a composting toilet as a self-contained treatment and disposal facility (30 TAC 285.2), and a permit and approved plan are required to construct an OSSF unless an exception in 285.3(f) applies; permits come from TCEQ or the local permitting authority. Whether NSF/ANSI 41 is required, and how household graywater must be handled with a composting toilet, was not confirmed.

TCEQ RG-472 On-Site Sewage Facility Rules Compilation

Electrical code (off-grid solar and wiring) NEC 2026

TDLR amended 16 TAC 73.100 to adopt the 2026 NEC as the state electrical code effective September 1, 2026 (replacing the 2023 NEC, effective since September 1, 2023), with a limited GFCI exception for certain outdoor outlets. Cities such as Houston review permits and inspect under the state minimum code. No statewide solar/off-grid-specific rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (9/1/2023).

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Utah

Rainwater collection Allowed, limits

Without registering, you may store rainwater in up to two covered containers of no more than 100 gallons each; with free registration with the Division of Water Rights, total storage may be up to 2,500 gallons. Water must be put to beneficial use on the same parcel where it is captured and does not create a water right (Utah Code 73-3-1.5).

Greywater reuse Permit needed

Graywater may be used for subsurface landscape irrigation under Utah Admin. Code R317-401, administered by local health departments that have Division approval to run a graywater program; a construction permit is required before building a system, and the system must be recorded on the property deed. Local health departments may be stricter or prohibit systems.

Composting toilets No state rule

No composting-toilet provision or NSF/ANSI 41 requirement was found in Utah's onsite wastewater rule (R317-4); that rule requires a dwelling's drainage system to receive all wastewater (bathroom, kitchen, laundry) and discharge to a public sewer or an approved onsite system. Check with your local health department.

Electrical code (off-grid solar and wiring) NEC 2023

Utah Code 15A-2-103(1)(g) adopts the 2023 NEC as part of the State Construction Code (version effective July 1, 2026; the version effective January 1, 2027 also lists the 2023 NEC). IAEI reports Utah's residential electrical requirements as based on the 2020 NEC, possibly via state amendments to the 2021 IRC; that split was not confirmed in the statute. No statewide solar/off-grid-specific rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (1/1/2025).

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Vermont

Rainwater collection Allowed, limits

NCSL's 2025 rainwater map (built from U.S. DOE FEMP data) lists Vermont as restricting rainwater collection and use: Rainwater used for non-potable, outdoor purposes only. We did not find the statute text itself in this check, so confirm details with your county health department or the state environmental agency.

Greywater reuse No state rule

No specific greywater-reuse allowance was confirmed. Vermont regulates wastewater systems through DEC's Wastewater System and Potable Water Supply Rules; check with the DEC regional office.

Vermont DEC Composting Toilet Guide (2020)

Composting toilets Permit needed

Composting and incinerating toilets require a permit from the Agency of Natural Resources (DEC) under the Wastewater System and Potable Water Supply Rules. DEC's fact sheet says toilets should be NSF-41 certified or equivalent and that a composting toilet can reduce leachfield size by 25%; at a primitive campsite one can be used without a permit if waste goes to a landfill.

Electrical code (off-grid solar and wiring) NEC 2023

The 2025 Vermont Electrical Safety Rules adopt the 2023 NEC; the Division of Fire Safety lists them as effective November 5, 2025. The rules are adopted by the Commissioner of Public Safety and the Electricians' Licensing Board and administered by the Division of Fire Safety. Whether they apply to owner-occupied single-family homes, and any solar-specific rule, was not confirmed. NFPA's enforcement map (as of August 3, 2026) lists: 2020 (1/1/2023); 2023 update underway.

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Virginia

Rainwater collection Permit needed

VDH's Rainwater Harvesting System Regulations (12VAC5-635, effective November 20, 2024) let Tier 1-3 non-potable systems (e.g., irrigation, toilet flushing) be installed without a permit, but the owner must file a registration form within 30 days of installation; rain barrels used only for Tier 1 uses are excluded. Potable (Tier 4) systems need VDH construction and operation permits.

Greywater reuse No state rule

Va. Code 32.1-248.2 directs the Board of Health to adopt regulations on gray water use (gray water excludes toilet wastewater); a final gray water regulation was not confirmed. Check with VDH or your local health district.

Va. Code 32.1-248.2

Composting toilets Allowed, limits

Under VDH's Sewage Handling and Disposal Regulations, all composting toilets must be NSF Standard 41 certified (12VAC5-610-980 B 3 c), and a sewage disposal system meeting 12VAC5-610-250 must still be provided for other household wastewater (laundry, bathing, handwashing, cooking).

12VAC5-610-980

Electrical code (off-grid solar and wiring) NEC 2020

The 2021 Virginia Uniform Statewide Building Code, effective January 18, 2024, uses the 2020 NEC. The statewide code is enforced by local building officials. No statewide solar/off-grid-specific rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2020 (1/18/2024); 2023 update underway.

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Washington

Rainwater collection Allowed, limits

No water right permit is needed to collect rooftop rainwater, as long as it is used on the property where it is collected and collected from existing structures built for another purpose (Ecology interpretive policy POL-1017, 2009). Local restrictions may apply where collection affects existing water rights, indoor use needs local building department approval, and drinking-water use depends on the county.

Greywater reuse Permit needed

WAC 246-274 sets three tiers: Tier 1 is untreated light greywater by gravity under 60 gallons per day per system (max 2 per building); Tiers 2 and 3 are under 3,500 gallons per day. Irrigation must be subsurface and seasonal, with a diversion valve to the permanent sewage system; local health jurisdictions decide whether Tier 1 is allowed and may be stricter. Greywater systems do not replace an approved on-site sewage system or sewer connection.

Washington DOH - Greywater reuse

Composting toilets Permit needed

Proprietary composting toilets must be tested to NSF/ANSI 41 and listed on DOH's registered products list, and the local health officer must issue installation and operational permits. If the building has potable water and produces greywater, the toilet must be combined with an approved on-site greywater treatment system or public sewer (DOH 337-016, August 2025).

Washington DOH 337-016 Water Conserving On-Site Wastewater Treatment Systems (Aug 2025)

Electrical code (off-grid solar and wiring) NEC 2023

WAC 296-46B-010 adopts the 2023 NEC, and the 2026 NEC replaces it effective December 31, 2026 (last amended by WSR 25-23-069, effective 12/19/2025). The Department of Labor & Industries or a city with its own electrical inspection program enforces. No statewide solar/off-grid-specific rule was found in this section. NFPA's enforcement map (as of August 3, 2026) lists: 2023 (4/1/2024); 2026 update underway (projected 12/31/2026).

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West Virginia

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists West Virginia as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Permit needed

Grey water systems are addressed in the DHHR sewage rule (64CSR47 section 6.15): manufactured systems need Commissioner approval, garbage disposals may not connect, and non-commercial systems need a septic tank (at least 1,000 gallons for up to four bedrooms) and a soil absorption field sized for a 30% water-use reduction. The rule text found is marked effective until 7/1/2025; the current version was not confirmed.

W. Va. Code R. 64-47-6 Individual Sewage Systems (Cornell LII)

Composting toilets Allowed, limits

Composting toilets must meet NSF Standard 41 and may be used only with an approved grey water treatment and disposal system (64CSR47 section 6.13). The rule text found is marked effective until 7/1/2025; the current version was not confirmed.

W. Va. Code R. 64-47-6 Individual Sewage Systems (Cornell LII)

Electrical code (off-grid solar and wiring) NEC 2020

The State Building Code (87CSR4, last effective 8/1/2022) adopts the 2020 NEC with exceptions (mini-split GFCI exemption until January 1, 2023; limited AFCI requirements for some renovations). The rule describes local jurisdictions that choose to adopt the State Building Code, so enforcement is local where adopted. No statewide solar/off-grid-specific rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2020 with WV amendments (8/1/2022).

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Wisconsin

Rainwater collection No state rule

No statewide limit on rain barrels was found. Using stormwater or clear water inside a plumbing system (e.g., toilet flushing) falls under the state plumbing code reuse rules (SPS 382.70) and DSPS review.

Wisconsin DSPS - Water reuse product approval checklist

Greywater reuse Permit needed

SPS 382.34(3)(a) allows graywater to be reused under SPS 382.70, whose Table 382.70-1 sets treatment standards by use (subsurface irrigation, toilet/urinal flushing, etc.). Systems require Department of Safety and Professional Services review; graywater may not be used for drinking, cooking or bathing.

Wisconsin DSPS - Water reuse product approval checklist

Composting toilets Allowed, limits

Composting toilet systems must conform to NSF Standard 41 and be listed by a testing agency acceptable to DSPS (SPS 391.10). Liquid from a composting toilet must go to a public sewer or a POWTS meeting SPS 383; whether a full POWTS is still required for household graywater was not confirmed.

Wis. Admin. Code ch. SPS 391 Sanitation

Electrical code (off-grid solar and wiring) NEC 2023

Wisconsin's updated state electrical code, based on the 2023 NEC with state changes and omissions, took effect September 1, 2026, replacing the code based on the 2017 NEC. DSPS enforces state building codes. No statewide solar/off-grid-specific rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2017 commercial (8/1/2018), residential (1/1/2020); 2023 effective 9/1/2026.

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Wyoming

Rainwater collection No state rule

No statewide rainwater harvesting statute or rule was found, and NCSL's 2025 map (built from U.S. DOE FEMP data) lists Wyoming as having no statewide law, so collecting rain from your roof is generally allowed. Cities and counties may still have rules, especially for indoor or drinking-water use; check with your county health or building department.

Greywater reuse Permit needed

Greywater systems meeting Wyoming DEQ Chapter 25 Section 17 are permitted by rule, but the owner must submit required information to the DEQ Water Quality Division before construction. Greywater may not pond, run off, leave the property or reach surface or groundwater; surface irrigation water should be disinfected; a diversion to the blackwater system is required.

020-25 Wyo. Code R. 25-17 Greywater Systems (Cornell LII)

Composting toilets No state rule

DEQ Chapter 25 does not name composting toilets; it covers sealed vault privies (Section 16) and lets systems not specifically covered be permitted case by case with an engineering report (Section 6). No NSF/ANSI 41 requirement was found. Check with DEQ or your county.

Electrical code (off-grid solar and wiring) NEC 2026

The Wyoming State Fire Marshal's electrical safety page lists the 2026 NEC among the codes that apply; its effective date was not confirmed (IAEI lists the 2023 NEC effective 7/1/2023). Local jurisdiction arrangements were not confirmed. No statewide solar/off-grid-specific rule was found. NFPA's enforcement map (as of August 3, 2026) lists: 2026 (7/1/2026).

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How this page was put together

Each state’s statutes, administrative code and agency guidance were checked on November 2, 2026, and linked directly. Where no state rule was found for rainwater, we used the NCSL’s 2025 rainwater map, which is built from the U.S. Department of Energy’s FEMP data. Electrical code editions come from state code agencies and NFPA’s NEC enforcement map (as of August 3, 2026); where a state adopted a newer edition after that date, both are shown. Spotted a change? Send a correction.

Frequently Asked Questions

Is it illegal to collect rainwater in any state?

No. Every state allows some rainwater collection. Colorado limits most homes to two barrels totaling 110 gallons for outdoor use, Utah requires free registration to store more than two 100-gallon containers (up to 2,500 gallons), and several states limit use to non-potable or outdoor purposes. Local rules can add requirements.

Are composting toilets legal in all 50 states?

Most states allow them, usually requiring an NSF/ANSI 41-certified unit. Most still require an approved septic or greywater system for sink, shower and laundry water, so a composting toilet rarely removes the need for a wastewater permit.

Is it legal to live off the grid?

Yes, in every state. What you have to follow are building, health and electrical codes: a permitted water source, an approved way to handle wastewater, and solar wiring that meets the electrical code your state or county enforces.

Do I need a permit for an off-grid solar system?

Usually, if your state or county enforces the NEC for homes. Some rural counties in states with local-only adoption have no electrical inspection, but insurers and lenders may still require code-compliant work. Check with your county building department.

Is greywater reuse legal?

Greywater reuse is allowed in most states, usually with a permit or design limits; simple laundry-to-landscape systems often need no permit. Several states treat greywater as wastewater that must go to a septic or sewer system. Check the state table and your county health department.