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Gray Water Do's and Dont's

Gray water is waste water from your washing machine, bathroom sink, bathtub or shower. Reusing water from you kitchen sink or dishwasher is illegal because of contamination risks. And, of course, you don't want to reuse what you flush in the toilet, which is known as "black water."

If you produce less than 400 gallons of gray water a day, you don't need a permit for recycling gray water. Older houses generate about 46 gallons of gray water per day per household member; new construction generates 35 gallons per person per day.

Recycling Graywater
Reuse of water from from washing machines and other appliances

  • An average saving of $3 to $4 per month depending on overall water use since Tucson Water's rates are based on consumption.

Potential gray water savings per day Average overall water use per day

35 gpc*                    46 gpc*                               120 gpc*
(New Homes)        (Older homes)                 (Typical Tucsonan)

*gpc = gallons per capita

(SOURCES: Tucson Water, Arizona Dept. of Environmental Quality)

Even if you don't need a permit, state regulations require that you:

  • Have a house that isn't in a flood plain.
  • Use gray water from only your residence for irrigation only on your property.
  • Do not use the water for irrigation of food plants, except citrus and nut trees.
  • Connect your gray water system to a septic or sewer system in case it has problems.
  • Have a secure cover for gray water storage for mosquito control and safety.

Some other Do's and Don'ts

Do:

  • Filter your gray water with something as simple as a stocking to trap hair and lint.
  • Frequently check your plants for evidence of over watering or damage from organic material in gray water.
  • Use gray water only for flood or drip irrigation.
  • Divert gray water to your sewer or septic system if you are laundering diapers or dyeing clothes.
  • Structure your irrigation system so it doesn't waste water by letting it percolate beyond the root zone.
  • Use PVC or ABS piping.

Don't:

  • Drink your gray water!
  • Reuse water that contains hazardous chemicals from photo labs, car parts or oily rags.
  • Allow your gray water to pond because it can increase health risks and provide breeding grounds for mosquitoes.
  • Reuse gray water for spray irrigation.
  • Irrigate root or leaf crops (such as carrots or lettuce) that you'll eat.
  • Reuse gray water if family members suffer from infectious diseases, such as diarrhea, hepatitis or internal parasites.

(SOURCE: Arizona Department of Environmental Quality, 1-800-234-5677)