Greywater laws by state: who lets you reuse your shower water

Only 7 states let a household put shower or laundry water on the garden without any permit: Arizona, California, New Mexico, Oklahoma, South Dakota, Texas and Washington. In another 13 states the rules use the word “greywater”, but the only system they describe is a smaller septic field for homes with composting toilets. The water goes underground, not to your plants.

Colorado shows how unsettled this still is. A 2013 law made greywater legal, but only in cities and counties that passed their own ordinance, and few did. On January 1, 2026, HB24-1362 reversed that default. Greywater is now authorized statewide unless a local government opts out.

This guide covers all 50 states. Each state's rule is linked to its official source. We also explain why the rules differ, which conditions nearly every state repeats, and what to check before you buy land or build a system.

How much of your water is greywater

Greywater is wastewater from showers, bathtubs, bathroom sinks and clothes washers. It has not touched toilet waste. Most states also leave out kitchen sinks and dishwashers. The best national measurements come from the Water Research Foundation's Residential End Uses of Water study (2016), which metered homes served by 23 utilities. A single-family home used about 138 gallons a day indoors, split up like this:

Showers, baths and laundry alone add up to about 54 gallons a day, or 40 percent of indoor use. Add bathroom sinks and it is close to half. Per person, the same study measured 58.6 gallons a day indoors. About 22 gallons of that came from the shower, bath and washer. So a two-person off-grid household produces roughly 45 gallons a day of the greywater most states allow you to reuse.

That figure matters for two reasons. First, it is small enough to fit under every state's no-permit limit except Washington's, which is 60 gallons a day of light greywater. Second, it is real water. EPA WaterSense estimates that outdoor watering is more than 30 percent of household use on average and can reach 60 percent in dry regions. On a well or hauled-water property, 45 gallons a day is about 1,350 gallons a month you don't have to pump or buy. The USGS estimated that self-supplied households, mostly on private wells, used an average of 77 gallons per person per day in 2015.

The four ways states handle it

We read every state's onsite wastewater rules, plus its plumbing code where the code deals with greywater, and sorted each state into one of four groups. The labels describe the path a household has to take. They don't rate whether a state is friendly to greywater.

• Permit-free tier 7 states. Some household systems are allowed without a permit if they meet written conditions: Arizona, California, New Mexico, Oklahoma, South Dakota, Texas and Washington.
• Permit required 24 states. The state has a greywater-specific approval path. In 12 of them it allows irrigation reuse. In the other 12 (Alabama, Connecticut, Florida, Kentucky, Maine, Massachusetts, Minnesota, Missouri, New Jersey, New York, Rhode Island and West Virginia), the path is a separate disposal field or tank, usually for homes with waterless toilets.
• Engineered or limited 8 states. Reuse is possible only through an engineered design, an experimental or innovative system approval, a variance, or a very narrow case: Delaware, Kansas, Louisiana, Nebraska, New Hampshire, South Carolina, Virginia and Wisconsin.
• No specific rules 11 states. We found no state greywater provisions. Greywater is sewage and goes to a permitted septic or sewer system: Alaska, Arkansas, Illinois, Indiana, Maryland, Michigan, Mississippi, North Dakota, Pennsylvania, Tennessee and Vermont.

Two cautions. First, “no specific rules” does not mean greywater is unregulated. In those states, discharging wash water onto the ground is an unpermitted sewage discharge. Second, a state-level permit-free tier does not override a county. New Mexico's rule, for example, says local ordinances still apply.

States with a no-permit tier, side by side

The seven no-permit tiers differ in more than their gallon limits. Arizona and Texas allow the most water. Washington allows the least and also bans pumps and storage. California sets no gallon limit, but its exemption covers only a single washing machine.

A few states come close without being permit-free:

• Wyoming: household systems up to 2,000 gallons a day are “permitted by rule”. DEQ issues no individual permit, but you must send it your name, the property description and the construction start date before you build (Chapter 25, Section 17).
• Oregon: Tier 1 is a low-cost general permit for up to 300 gallons a day of untreated graywater, used for subsurface irrigation (OAR 340-053-0110).
• Colorado: single-family systems are capped at 400 gallons a day and still go through local approval.

For comparison, the Uniform Plumbing Code that many western states start from requires a permit for every greywater system. Its only concession to small homes is that systems up to 250 gallons a day don't need a registered design professional.

All 50 states

Filter by approach or garden reuse path, or search for a state. The “garden reuse path” column separates states that let greywater irrigate plants from states whose greywater rule is only a disposal field. Each row links to the rule we read. State names link to our state guides, which cover septic permits, wells and building codes.

Rules checked October 2026 from state administrative codes, statutes and agency guidance. Where a state's plumbing code adopts a model-code greywater chapter but the state has no greywater rule or guidance of its own (Maryland, for example), we list the state's onsite rules. Louisiana's row relies on a 2015 copy of the Sanitary Code. Ohio's relies on Ohio State University Extension's summary of its rule. Oklahoma's relies on EPA's summary of the statute, because the official sites could not be reached. Confirm those three with the agency.

Why the rules differ so much

Greywater is sewage under most old laws

Onsite wastewater codes were written to keep sewage underground and away from wells. Most define sewage to include bath and laundry water. Mississippi's on-site rules, for example, include “bath and toilet waste, residential laundry waste, residential kitchen waste”. Pennsylvania's onlot rules never use the word greywater at all. Without a carve-out, a pipe from the washing machine to the orchard is an unpermitted sewage discharge. Every state that allows greywater reuse had to write a specific exception, so the default in the 11 states without one is simply that the exception was never written.

Health officials expect pathogens

Greywater contains skin bacteria, traces of fecal matter from bathing and laundry, and food residue. Colorado's regulation says plainly that “graywater is expected to carry human pathogens”. The Uniform Plumbing Code bars watering root crops and food crops that touch the soil. Hence the rules that recur almost everywhere: subsurface only, no spraying, no ponding and short storage times. Each of them is designed to keep people and pets from touching the water.

Water rights in the West

In prior-appropriation states, wastewater that returns to a stream or aquifer can be water someone downstream has a right to. Colorado wrote that concern into statute. Greywater may be used “only in accordance with the terms and conditions of the decrees, contracts, and well permits applicable to the use of the source water rights or source water and any return flows”. In practice, a household on an exempt domestic well should confirm that its well permit allows the outdoor use greywater would feed. A small lawn or garden on a domestic well can be a permit question in its own right. Our well permits and water rights guide covers the state rules.

Drought states moved first

The no-permit tiers are concentrated in dry states:

• Arizona adopted its Type 1 general permit effective January 16, 2001.
• New Mexico followed after HB 114 in 2003. NMED describes its rules as more protective than other southwestern states'.
• Texas wrote its residential exemption into the Health and Safety Code. TCEQ amended the rules in 2016 to cover what it calls “alternative onsite water”.
• Washington's three-tier rule took effect July 31, 2011.

Wetter states have had less reason to change sewage codes that already worked.

Colorado's opt-in experiment

Colorado shows what happens when permission depends on local action. HB13-1044 authorized graywater in 2013, and Regulation 86 took effect June 30, 2015. Both applied only where a city or county adopted an ordinance. A tally by the nonprofit Colorado WaterWise lists seven local programs: Denver (2016), Castle Rock (2018), Pitkin County, Golden, Broomfield, Fort Collins and Grand Junction. It counts roughly 3 homes in Denver, roughly 30 in Castle Rock and none in the other five.

HB24-1362 took effect January 1, 2026, and flipped the default. A person may now install graywater treatment works statewide under Regulation 86. A county or city that wants to stop it must adopt a prohibition and notify the state health department. The law also limits indoor systems to new construction unless a local ordinance says otherwise. Expect local programs to keep changing through 2026 and 2027, and ask the county where it stands.

Laundry-to-landscape: how California got there

California shows how much the details of a rule matter. Residential greywater was once regulated by the Department of Water Resources. In 2008, SB 1258, the “Showers to Flowers” bill, moved the job to the Department of Housing and Community Development. HCD rewrote the code on an emergency basis. The new rules took effect August 4, 2009 and created a permit exemption for a single clothes-washer system.

That exemption is now in Chapter 15 of the 2025 California Plumbing Code, effective January 1, 2026. It applies only at a one- or two-family home and only to one washing machine. The washer's own pump pushes water through a labeled diverter valve into mulch basins around trees and shrubs. The code requires at least 2 inches of mulch, rock or soil over each outlet, bars any other pump, and requires an operation manual. Water used to wash diapers must go to the sewer. Anything bigger is a “simple system”, up to 250 gallons a day, or a “complex system”, above that, and needs a construction permit unless the local agency waives it.

Utilities have built programs around these no-permit tiers. Tucson, Arizona, reimburses 50 percent of qualifying costs, up to $1,000, after a free workshop. The city notes that no permit is needed to tap an existing washer stub-out, but changing drain plumbing from any fixture needs one. That split between the exempt system and the plumbing that feeds it applies in most states.

Greywater and composting toilets

For many off-grid buyers, greywater comes up because of the toilet. A home with a composting toilet produces no black water, so the obvious question is whether it needs a septic system at all. In most states the answer is yes, but a smaller one. For a lot of eastern and midwestern states, a smaller system for the leftover greywater is the only greywater rule there is:

• New York: 75 gallons a day per bedroom when a waterless toilet is used, against 110 to 150 for homes with flush toilets.
• Rhode Island and Minnesota: a graywater system sized at 60 percent of normal design flow.
• Connecticut: a septic tank and leaching system at least half the normal size, where no flush toilets are connected.
• Massachusetts: a leaching area up to 50 percent smaller, with a 1,000-gallon tank or an approved filter.
• Missouri: design flow reduced up to 40 percent.
• West Virginia: a standard absorption field with a 30 percent flow reduction.
• Maine: a “primitive” 25-gallon-a-day grey water field for a cabin with hand-carried water.
• New Hampshire: a stone-filled mini dry well, but only for a structure with no running water.

New Jersey adds a hurdle: before the health authority can approve a greywater system paired with a waterless toilet, the owner needs a variance from the state plumbing subcode.

The practical lesson for a composting-toilet plan is to budget for a permitted greywater disposal system and treat garden reuse as a possible addition. Where a state allows irrigation reuse, the rules almost always require a valve that sends water back to the septic system or sewer when the ground is saturated or frozen. Washington's Department of Health calls greywater irrigation seasonal and says it does not replace a sewer or septic system. Our septic and composting toilet guide covers soil tests and system choices.

The conditions almost every state repeats

Read enough greywater rules and the same list appears with small variations. If a system breaks one of these, it is almost certainly outside any exemption.

• No kitchen water. Kitchen sinks and dishwashers are excluded in Arizona, California, Colorado, Delaware, Kentucky, New Mexico, Texas and the Uniform Plumbing Code. Georgia and Nebraska classify kitchen water as black water.
• No diaper water or water from washing similarly soiled items (California, Arizona and New Mexico).
• Subsurface or under mulch. No spraying. Utah, Hawaii and Nevada allow subsurface irrigation only. Wyoming allows surface irrigation only with disinfection.
• No ponding or runoff, and nothing reaching a storm drain, ditch or neighbor's land.
• Short or no storage. Twenty-four hours in New Mexico, Oregon, Kansas and Ohio's small systems. None at all in Washington's Tier 1. Stored greywater turns septic and smells within hours.
• Distance from groundwater and wells. At least 5 feet to groundwater in Arizona and New Mexico, and 100 feet from wells in New Mexico, Montana and Wyoming.
• A diverter valve that sends water back to the sewer or septic, plus an overflow connection.
• Limits on food crops. Fruit and nut trees are generally fine. Root crops and leafy greens that touch the soil are not.

Legal, permitted and already installed

Many greywater systems run without any permit, so on a rural property there is a real chance you will find one. A hose from the washer to the fruit trees is the classic example. Whether that is a problem depends on the state and on how the system was built.

In a permit-free state, a system that meets every condition is lawful even though no record of it exists. A system that sprays, ponds, stores water for days or takes kitchen water is not, because breaking a condition takes it outside the exemption. In a state with no greywater rules, any discharge of wash water to the ground is an unpermitted sewage discharge. It can be cited if a neighbor complains or an inspector notices it. The common triggers are a septic inspection at sale, a remodel permit and a failing drainfield.

We don't recommend building an unpermitted system to save time. The risks are concrete. The county can order removal. A septic system sized with a greywater credit can fail if the greywater line is later reconnected. Insurers and lenders may treat unpermitted plumbing as a defect.

Before you buy or build

1. Find your state's path. Use the table above, and read the linked rule rather than a summary. Note the gallon limit, the allowed fixtures and the conditions.
2. Call the county or district health department. Ask whether it has its own greywater ordinance, registration or prohibition. In Colorado, also ask whether the county or city has opted out under HB24-1362. In Utah, ask whether the local health department is approved to permit graywater systems at all.
3. Check the water source. On a well, read the well permit's allowed uses. In prior-appropriation states, ask the state engineer or water resources agency whether outdoor irrigation from greywater is within the permit. See our off-grid water guide for budgeting supply.
4. Size the septic system for full flow anyway. Most rules require greywater to divert back to the septic system or sewer in wet or frozen weather, and Kansas and Nevada say the onsite system cannot be downsized because of greywater reuse.
5. Plan the plumbing at construction. Separate drain lines from showers, bathroom sinks and the washer cost little in new construction and a lot later. In Colorado, indoor systems are limited to new construction by default.
6. Pick soap and plants to match. Greywater carries salts and boron from detergents. Use it on established trees, shrubs and mulched perennials, not root vegetables or leafy greens.
7. Keep the records. Save the permit, registration or notice, the as-built drawing and the operating manual where the rules require one. Hand them to the next owner. The 55-point buyer checklist covers the rest of the property.

Greywater rules are one piece of a state's off-grid picture. Compare them with rainwater harvesting laws, composting toilet rules and our 50-state comparison before choosing where to buy.