Graywater Systems and Rules

What is graywater?

Graywater is wastewater from showers, bathroom sinks and laundry. It does not include toilet water or, in most definitions, kitchen sink and dishwasher water, though the definition varies. Graywater is not clean water. It can carry soap, hair, skin oils, germs and chemicals.

The idea of reusing it for irrigation appeals to many rural households, especially in dry regions.

Keep in mind that laundry water carries lint, soaps and sometimes dyes. Even in places that allow reuse, the water usually must leave through a design that avoids pooling and runoff.

Is it allowed where I live?

Rules vary widely. Some states allow certain simple graywater uses with or without a permit. Others require permits and inspections or prohibit it. Counties and local health departments may add their own rules. Some areas treat any graywater outside the septic system as illegal discharge.

Do not rely on a website from another state or on a neighbor's story. Ask your county health department and your state environmental or health agency what applies to you before you change any plumbing.

Ask your health office whether you need a permit even for a simple laundry setup. Some places have a short list of low risk setups, and others make no exceptions.

What does it have to do with my septic system?

If you divert graywater away from a septic tank, the system may have a different load, and some regulators have rules about it. If you use a septic system and make changes to it, you may need permits and a review. Ask your septic professional and health office before altering plumbing.

Also ask whether your system was sized with graywater included, since the answer can change what is allowed.

Never connect graywater to a toilet drain or to a drinking water line, and never cross connect any pipes. A licensed plumber can explain backflow and why it matters.

What are the health and safety concerns?

Graywater can contain germs, especially laundry water from washing soiled clothes or diapers. It should not be stored for long, since it can turn bad and smell. It should not touch edible parts of plants in some designs, and it should not pool where children, pets or livestock can reach it.

Use only soaps and detergents that are suitable. Avoid bleach, boron products and salt heavy products, which can harm plants and soil. Ask extension for guidance on products that suit garden use.

• Do not store graywater for long
• Keep it off edible parts of plants unless local guidance allows
• Keep children and animals away from it
• Choose plant friendly cleaners

What kinds of systems exist?

Simple laundry to garden setups and branched drain systems are the most common household approaches, and more complex systems add tanks, pumps and filters. Complexity raises both cost and the risk of problems.

Any system needs a proper design, correct materials and a place for water to go during wet weather and freezing. Ask a licensed plumber who knows local rules rather than buying a kit without checking.

Winter is a special problem. Frozen pipes, cold soil and low plant demand make year round reuse difficult in many regions, so a plan needs a safe place for the water to go when the garden is dormant.

How do I get started the right way?

Contact your county health office first and ask for the written rules. Ask about permits and who inspects. Then talk to a licensed plumber or designer. Do not start with the purchase.

Think about other water saving steps that need no permit, such as fixing leaks, using efficient fixtures and collecting rain where it is legal, which also varies by state.

Keep notes about what the health office told you, including names and dates, and keep copies of any permit.

Are there simpler ways to save water first?

Before reuse, cut what you send down the drain. Fix leaks, install efficient fixtures, run full loads of laundry and use a basin to catch cool water while the shower warms up for plants that tolerate it. These steps help your septic system and your well at the same time, and they need no permit.

Rain barrels and other rain collection are limited in some states, so check your state agency before you set one up. Keep any container covered so mosquitoes cannot breed in it.

Talk with your extension office about drought tolerant plants, mulching and watering at the right time of day. Good garden practice often saves more water than any plumbing project.

Last reviewed: November 12, 2026. Written by the Rural Farm Life Editorial Team. See our editorial policy.