Rainwater harvesting laws by state
Collecting rain is legal across the United States. What changes from state to state is how much you can keep, whether it needs a permit and how it may be used indoors.
What to know first
Rainwater rules come from two directions. In much of the West, water law treats precipitation as part of a stream system already claimed by senior water rights, so states such as Colorado cap how much a household may store. Elsewhere, the legal question is less about collection than about plumbing: bringing rainwater indoors, and especially drinking it, brings in plumbing codes, health rules and treatment requirements.
Of the 50 states, we found no statewide restriction on collection in 35, 5 actively encourage it, and 10 set limits or conditions. A “no restriction” status does not mean anything goes: counties and cities can regulate tanks through zoning, setbacks and building permits, and a homeowners’ association can restrict visible barrels.
For an off-grid home, the more important question is often whether rain can serve as the approved potable supply. Read our water supply guide on storage and dry periods, then run your roof size and rainfall through the rainwater calculator.
State-by-state table
Filter by status or search for a state. Each summary links to the official source we relied on, and each state name opens the full guide. Statuses describe state-level rules; counties, cities and health districts can add requirements.
50 states
| Alabama | No statewide restriction found | No statewide limit on collecting roof runoff was found, and the state extension service promotes rain barrels and cisterns. Potable plumbing connections may trigger local plumbing permits and backflow protection.Alabama Cooperative Extension System: A Homeowner's Guide to Rainwater Harvesting in Alabama Source | 56.9 in |
|---|---|---|---|
| Alaska | No statewide restriction found | No state rule limiting roof rainwater catchment was found. Alaska water rights rules address appropriation from natural surface and groundwater sources. Treat and test catchment water used for drinking.Alaska DNR: Water Rights Source | 37.6 in |
| Arizona | No statewide restriction found | No statewide cap or permit for roof rainwater catchment was found, and the University of Arizona extension promotes harvesting for landscapes. Drinking-water use needs treatment and testing.University of Arizona Cooperative Extension: Harvesting Rainwater for Landscape Use (AZ1344) Source | 11.7 in |
| Arkansas | Allowed with limits | Rainwater collection is not banned. Systems connected to building plumbing fall under the Arkansas Plumbing Code administered by the Department of Health. Ask the Department of Health which design and plumbing rules apply before connecting a system indoors.ADH: Plumbing and Natural Gas Program Source | 52.5 in |
| California | Encouraged | Under the Rainwater Capture Act of 2012, using rainwater collected from rooftops does not require a water right permit. Building standards for capture systems still apply, and potable use needs local approval.California Water Code § 10574 (Rainwater Capture Act of 2012) Source | 22.3 in |
| Colorado | Allowed with limits | Qualifying homes may use up to two rain barrels totaling 110 gallons for outdoor use on the same property. Broader rooftop collection is limited to certain well-permit holders with a separate DWR permit.Colorado General Assembly: HB16-1005 Residential Precipitation Collection Source | 18.0 in |
| Connecticut | No statewide restriction found | No state permit or volume cap for rain barrels was identified, and DEEP promotes rain barrels for lawn and garden use. Rainwater systems plumbed into a building fall under the state building and plumbing code.P2 View newsletter, Summer 2007 — rain barrels (Connecticut DEEP) Source | 48.7 in |
| Delaware | No statewide restriction found | A 2015 PNNL report for the US Department of Energy found no Delaware rainwater harvesting regulations. No state permit or volume cap was identified; plumbed systems may fall under local plumbing codes.Rainwater Harvesting: State Regulations and Technical Resources (PNNL-24347, 2015) Source | 45.9 in |
| Florida | No statewide restriction found | A 2015 PNNL report for the US Department of Energy found no Florida rainwater harvesting regulations and noted some local incentives. No state permit or volume cap was identified.Rainwater Harvesting: State Regulations and Technical Resources (PNNL-24347, 2015) Source | 54.4 in |
| Georgia | No statewide restriction found | No state volume cap or permit for collection was identified. A 2015 PNNL report for the US Department of Energy notes that Georgia's state plumbing code allows rainwater harvesting.Rainwater Harvesting: State Regulations and Technical Resources (PNNL-24347, 2015) Source | 50.4 in |
| Hawaiʻi | No statewide restriction found | DOH does not regulate rainwater catchment on individual homes. It recommends University of Hawaii guidelines and testing for E. coli, turbidity, lead and copper, and subsidizes annual lead and copper tests.Rainwater Catchment — Hawaii DOH Safe Drinking Water Branch Source | 61.7 in |
| Idaho | No statewide restriction found | No state permit or volume cap was identified. A 2015 PNNL report for the US Department of Energy says Idaho allows rainwater harvesting under a clarification from the Office of the Attorney General.Rainwater Harvesting: State Regulations and Technical Resources (PNNL-24347, 2015) Source | 23.7 in |
| Illinois | Allowed with limits | The Illinois Plumbing Code regulates rainwater harvesting for non-potable uses under CSA B805/ICC 805. IDPH plan approval is required above 5,000 gallons of storage or for uses outside that standard.Illinois Plumbing Code, Section 890.3000 (IDPH second notice text) Source | 40.7 in |
| Indiana | No statewide restriction found | No Indiana statute or agency rule restricting household rainwater collection was found, and no volume cap was identified. Potable use and plumbing connections remain subject to plumbing and health rules.Water Availability, Use and Rights FAQ Source | 43.6 in |
| Iowa | No statewide restriction found | No Iowa statute or DNR rule restricting household rainwater collection was found. DNR water use permits apply only to withdrawals of 25,000 gallons or more per day.Water Allocation and Use Source | 35.5 in |
| Kansas | Allowed with limits | No Kansas rule specific to rooftop rainwater was found. Domestic use, including household needs and up to two acres of garden and lawn, needs no appropriation permit; non-domestic uses generally require one.K.S.A. 82a-728 Source | 29.0 in |
| Kentucky | No statewide restriction found | No Kentucky statute or rule restricting household rainwater collection was found. The state notes cisterns are used for drinking water and advises owners to test them annually, since quality is not state regulated.Water Well Information for Homeowners Source | 50.4 in |
| Louisiana | No statewide restriction found | No Louisiana statute or rule restricting household rainwater collection was identified, and no volume cap was found. Potable use and plumbing connections remain subject to state plumbing and health rules. | 59.7 in |
| Maine | No statewide restriction found | No Maine statute or rule restricting or capping rainwater collection was identified. The wastewater rule recognizes homes supplied from cisterns or hand-carried water through its limited and primitive system categories.Subsurface Wastewater Disposal Rule, 10-144 CMR 241 (definitions of limited and primitive systems) Source | 45.5 in |
| Maryland | Encouraged | Rainwater harvesting is one of the environmental site design practices listed in Maryland's stormwater regulations. No state permit requirement or volume cap for household collection was identified.COMAR 26.17.02.08 — Stormwater Management Criteria Source | 45.2 in |
| Massachusetts | No statewide restriction found | No state statute or regulation restricting household rainwater collection was identified. State water withdrawal registration applies only above 100,000 gallons per day, far beyond household scale.310 CMR 36.03 — Definitions (Threshold Volume), Water Management Program (LII) Source | 48.6 in |
| Michigan | No statewide restriction found | No Michigan law restricting rainwater collection was identified. Michigan's plumbing code adoption excludes the IPC nonpotable water chapter (sections 1301–1304), so state plumbing rules give no rainwater system standards.Mich. Admin. Code R. 408.30701 — Michigan Plumbing Code adoption (LII) Source | 33.9 in |
| Minnesota | Allowed with limits | The Minnesota Plumbing Code allows nonpotable rainwater catchment from impervious roofs for toilets, irrigation and similar uses. Plumbed systems need a permit, filtration and disinfection; potable use is not covered.Summary of Minnesota's Water Reuse Regulation — Rainwater, Onsite Non-potable Reuse (US EPA) Source | 28.6 in |
| Mississippi | No statewide restriction found | No Mississippi statute or rule restricting rooftop rainwater collection was identified. State water-use permits exempt surface water diversions for domestic single-residence purposes.11 Miss. Admin. Code Pt. 7, Ch. 1 — Surface Water and Groundwater Use and Protection Regulations Source | 58.5 in |
| Missouri | No statewide restriction found | No state statute or rule restricting residential rainwater collection was found, and a federal PNNL review listed no Missouri regulations. Local plumbing codes govern indoor connections.Rainwater Harvesting State Regulations and Technical Resources (PNNL-24347) Source | 43.5 in |
| Montana | No statewide restriction found | No Montana statute or rule specific to rooftop rainwater collection was found, and a federal PNNL review listed none. Montana uses prior appropriation, so large diversions could raise water-right questions.Rainwater Harvesting State Regulations and Technical Resources (PNNL-24347) Source | 18.9 in |
| Nebraska | No statewide restriction found | No Nebraska statute or rule restricting residential rainwater collection was found, and a federal PNNL review listed none. Local plumbing codes govern indoor use.Rainwater Harvesting State Regulations and Technical Resources (PNNL-24347) Source | 24.2 in |
| Nevada | Allowed with limits | NRS 533.027 exempts de minimis collection of precipitation from the rooftop of a single-family dwelling for nonpotable domestic use from water-right law. Potable use and larger collection are not covered.NRS 533.027 — De minimis collection of precipitation Source | 10.2 in |
| New Hampshire | No statewide restriction found | No New Hampshire statute or rule restricting residential rainwater collection was found, and a federal PNNL review listed none. Plumbing code governs any indoor connection.Rainwater Harvesting State Regulations and Technical Resources (PNNL-24347) Source | 47.9 in |
| New Jersey | No statewide restriction found | No New Jersey statute or rule restricting residential rainwater collection was found, and a federal PNNL review listed none. Indoor connections fall under the UCC plumbing subcode.Rainwater Harvesting State Regulations and Technical Resources (PNNL-24347) Source | 47.6 in |
| New Mexico | Encouraged | The State Engineer encourages roof harvesting for on-site irrigation and domestic uses. Most homeowners need no state permit, but collection should not reduce natural runoff and water may not be appropriated elsewhere.Rainwater Harvesting — Office of the State Engineer Source | 13.8 in |
| New York | No statewide restriction found | A federal review found no statewide rainwater harvesting regulations in New York. No volume cap or water-right permit applies; potable use would fall under health and plumbing rules.Rainwater Harvesting State Regulations and Technical Resources (PNNL-24347) Source | 43.5 in |
| North Carolina | Allowed with limits | Rainwater harvesting is allowed and addressed through the North Carolina Plumbing Code following Session Law 2009-243. No volume cap was identified; plumbing code provisions govern indoor non-potable systems.Rainwater Harvesting State Regulations and Technical Resources (PNNL-24347) Source | 50.8 in |
| North Dakota | No statewide restriction found | A federal review found no rainwater harvesting regulations in North Dakota. No permit, volume cap or potable-use rule specific to rainwater was identified.Rainwater Harvesting State Regulations and Technical Resources (PNNL-24347) Source | 18.9 in |
| Ohio | Allowed with limits | Rainwater cisterns used for household water are private water systems needing a local board of health permit. New cisterns must hold at least 2,500 gallons per dwelling and meet construction and treatment rules.Ohio Adm.Code 3701-28-12, Construction of cisterns, reservoir tanks, hauled water storage tanks and roof washers Source | 41.1 in |
| Oklahoma | Encouraged | No state permit or volume cap for collecting rainwater was found. The 2012 Water for 2060 Act promotes rainwater and graywater use through pilot projects and public information.HB 3055 (2012), Water for 2060 Act Source | 36.4 in |
| Oregon | No statewide restriction found | ORS 537.141 exempts collecting and using precipitation from rooftops and other artificial impervious surfaces from water-right permit requirements. Indoor plumbing connections fall under the state plumbing code.ORS 537.141, Uses exempt from water right permit Source | 32.1 in |
| Pennsylvania | No statewide restriction found | No Pennsylvania statute or regulation restricting residential rainwater collection was found. Connecting a cistern to household plumbing would fall under the UCC and local code officials. | 45.0 in |
| Rhode Island | No statewide restriction found | No Rhode Island statute or rule restricting residential rainwater collection was found. Connecting a cistern to household plumbing would go through the local building official under the state code. | 49.1 in |
| South Carolina | No statewide restriction found | No South Carolina statute or regulation restricting residential rainwater collection was found. Connecting a cistern to household plumbing would fall under locally enforced state plumbing codes. | 48.3 in |
| South Dakota | No statewide restriction found | No South Dakota statute or DANR guidance found addresses rooftop rainwater collection, and no volume cap was identified. Household water use falls under the state's domestic-use exemption from water-right permits.Water Rights Summary Source | 21.2 in |
| Tennessee | No statewide restriction found | No state volume cap or permit for rain barrels was found, and UT Extension promotes them. Indoor plumbing connections and graywater systems fall under plumbing permits.W276 Rain Barrels Make Good Sense Source | 55.1 in |
| Texas | Encouraged | Legal with no statewide volume cap. Equipment is exempt from state sales tax, and new HOA bans are limited. Potable systems tied to public water need cross-connection safeguards and licensed plumbers.TWDB: Rainwater Harvesting FAQ Source | 28.6 in |
| Utah | Allowed with limits | Two covered containers of up to 100 gallons each need no registration. With Division of Water Rights registration, storage up to 2,500 gallons is allowed on the same parcel.Utah Code § 73-3-1.5 (Collection of precipitation) Source | 13.5 in |
| Vermont | No statewide restriction found | No state permit or volume cap was identified. Vermont's stormwater manual covers rooftop rainwater harvesting for non-potable uses such as toilet flushing and irrigation; potable use is not addressed there.Summary of Vermont's Water Reuse Guideline or Regulation — US EPA Source | 46.0 in |
| Virginia | Allowed with limits | Legal. Containers up to 100 gallons are unregulated. Non-potable systems need no permit but must be registered within 30 days; potable systems need VDH construction and operation permits.Rainwater Harvesting — VDH Source | 45.8 in |
| Washington | No statewide restriction found | Ecology's 2009 interpretive policy says on-site storage and use of rooftop rainwater needs no water-right permit. Ecology may restrict new systems if they harm instream flows or existing rights.Interpretive Statement on rooftop and guzzler rainwater (WSR 09-21-031) Source | 43.2 in |
| West Virginia | No statewide restriction found | No West Virginia statute or rule restricting rainwater collection was identified, and no state incentive exists. Plumbing rainwater into a home's water system raises plumbing-code and health questions. | 47.0 in |
| Wisconsin | No statewide restriction found | We found no Wisconsin law limiting rain barrels or cisterns. Bringing rainwater indoors for any use brings in the state plumbing code; ask the county or a licensed plumber before plumbing a system. | 34.0 in |
| Wyoming | No statewide restriction found | No Wyoming statute or State Engineer guidance addressing household rooftop rainwater collection was found. Wyoming is a prior appropriation state, so ask the State Engineer before building large capture systems. | 16.0 in |
Checked October 2026. Laws change; open the linked source before relying on a summary. Found an error? Tell us.
Common questions
Is rainwater harvesting legal in every state?
Collecting rain from a roof is legal in every state, but 10 states attach conditions such as volume caps, permits, registration or limits tied to water rights: Arkansas, Colorado, Illinois, Kansas, Minnesota, Nevada, North Carolina, Ohio, Utah, Virginia. Elsewhere we found no statewide restriction on collection, although plumbing, health and building rules still govern indoor and drinking-water use.
Which states encourage rainwater collection?
California, Maryland, New Mexico, Oklahoma, Texas actively encourage collection through incentives, tax treatment, design guidance or building standards. Check the linked source for each state to see what the incentive covers and whether it applies to a whole-house potable system.
Can rainwater be the only water supply for a house?
Sometimes. Whether a building department will accept rainwater as the sole potable source for a certificate of occupancy is decided locally and is often the real limit, not collection law. Ask the building and health departments before buying, and expect requirements for treatment, testing and storage.
How much rainwater can a roof collect?
About 0.623 gallons per square foot per inch of rain, before losses. A 1,500 sq ft roof in 20 inches of annual rain yields roughly 15,000 gallons at 80% efficiency. Use the rainwater calculator to test your own figures and size storage for dry spells.