University of Wyoming Extension News

Household greywater provides alternative water source for landscapes

Water drained from baths, showers, washing machines, laundry tubs and bathroom and kitchen sinks, called greywater, can provide a secondary source of water for landscape plants while conserving potable water, according to an educator with University of Wyoming Extension.

“Capturing greywater and using it on your landscape during this summer’s drought may reduce the demand on your potable well water,” said Sandra Frost, based in Park County.

According to Frost, a family of four generates 100 gallons of greywater a day, including warm-up water that could be used on landscape plants.

“Warm-up water is the water you run out of household faucets before the hot water gets to the sink or shower,” said Frost. “Warm-up water is clean, ready to use on your landscape or vegetable garden and has no health issues. Just keep a bucket or container handy and catch it.”

However, she said greywater, not including warm-up water, may contain bacteria, organic matter and other potential pathogens and recommends its use only on landscape plants and not vegetable plants to avoid possible contamination with pathogens.

“Greywater is not potable by pets or humans due to organic matter and dissolved chemicals,” said Frost.

Greywater systems range in complexity from a simple bucket to integrated, parallel plumbing lines built into a house.

Frost said greywater may contain nitrogen and phosphorous needed by plants and may also reduce the demands on septic systems or municipal sewage treatment facilities by reducing the volume of water that must be treated.

The Wyoming Department of Environmental Quality (DEQ) regulates greywater systems in the state. A greywater system can be constructed without a Wyoming DEQ permit if it meets all of the 11 DEQ requirements. No application for a permit or fee is required if all the conditions are met, said Frost. A list of the permit-by-rule requirements is at https://deq.state.wy.us/wqd/www/Permitting/Downloads/GWPolicy.pdf.

“Wyoming’s greywater policy is based upon the idea do no harm,” said Frost. “If your greywater system is not harming anybody, degrading environmental quality or causing a nuisance, it is probably covered under “permit-by-rule” as defined in Chapter 16 of the DEQ Water Quality Rules and Regulations.”

DEQ publishes the handbook Special Greywater Design Considerations for the State of Wyoming to assist in the design of greywater systems in Wyoming’s climate available at https://deq.state.wy.us/wqd/www/greywater.htm.

Greywater does not include water in the household sewage systems (blackwater).

Health concerns, plant tolerances and soil texture determine where and how much greywater is appropriate for a garden. Greywater should be used within 24 hours to avoid the growth of pathogens and to reduce odor.

For more information, contact Frost at 307-754-8836 or email her at sfrost1@uwyo.edu.