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Graywater

Under Oregon law, graywater includes wastewater discharged from showers and bathtubs, bathroom sinks, kitchen sinks and laundry machines. Graywater does not include toilet discharge, garbage wastes (kitchen sinks with garbage disposal units) or wastewater contaminated by soiled diapers.

Graywater can be contaminated with organic matter, suspended solids or potentially pathogenic microorganisms. However, if appropriately collected and handled, graywater can be safely reused for flushing toilets and urinals as well as irrigating certain trees and plants. Reuse of graywater reduces the demand on other sources of water, such as potable water, surface water and groundwater.

Oregon recognizes three types of graywater

  • Type 1: Untreated graywater or graywater that has passed through a physical process to remove solids, fats, oils and grease.
  • Type 2: Graywater that has passed through some type of chemical or biological process, such as a wetland, to further reduce solids and organic matter.
  • Type 3: Type 2 graywater that is also disinfected.

Regulations and other information

DEQ regulates graywater reuse and disposal systems under Oregon Administrative Rules Chapter 340, Division 53, which establishes a policy that encourages graywater reuse while protecting public health safety and welfare, public water supplies and waters of the state. These rules are based on recommendations from DEQ's Graywater Advisory Committee.

The rules define three types of graywater (Type 1, Type 2 and Type 3), based on level of treatment, and identify specific beneficial purposes, such as landscape irrigation, for each type of graywater. The rules also establish treatment and monitoring requirements, setbacks, access and exposure controls, and site management practices necessary to protect public health and the environment. 

Technical assistance

Contact

Pat Heins
Biosolids and Water Reuse Coordinator