Grey-Water Recycling: Legal Rules and DIY Systems for U.S. Households
Every shower, sink, and laundry load sends gallons of usable water down the drain. Grey-water recycling captures that lightly used water and redirects it—usually for yard irrigation or toilet flushing.
Most states allow residential grey-water systems, but regulations vary. Some require permits and licensed installers; others allow simple, non-storage “laundry-to-landscape” setups without paperwork. California, Arizona, Texas, and New Mexico are among the most grey-water-friendly states.
A basic DIY system starts with diverting laundry water (from a machine without bleach or harsh chemicals) into mulch basins around trees and shrubs. You’ll need a diverter valve, gravity-friendly layout, and safe soaps labeled “biocompatible.”
Never reuse water from kitchen sinks or toilets—that’s black water, and it's heavily regulated. Grey water must be used within 24 hours to avoid microbial buildup. Storage is rarely allowed without treatment.
Done right, grey-water recycling cuts outdoor water use by up to 50%, saves money, and conserves a precious resource—especially in drought-prone areas.
Sources
US Environmental Protection Agency, “Water Recycling and Reuse,” 2023
https://www.epa.gov/waterreuse
Greywater Action, “State-by-State Regulations,” 2024 https://greywateraction.org
California Department of Water Resources, “Graywater Systems,” 2023
https://water.ca.gov/Programs/Water-Use-And-Efficiency/Graywater
University of Arizona, “Water Harvesting Guidance Manual,” 2023 https://wrrc.arizona.edu/publications/water-harvesting
