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System Requirements for Graywater Rebate

Graywater laundry to landscape rebate
Click here for an example laundry to landscape system that meets the rebate requirements listed below, as well as a sample parts list. Provided for reference purposes only.

Landscape Requirements

  • All graywater must be distributed from the washing machine to a pre-approved landscape area that is large enough to absorb the graywater

    • The district can provide assistance with determining the surface area required using the customer responses from their self-guided pre-inspection responses (from Step 1).

    • If one or more valved zones are installed, each zone must be of adequate size to receive the graywater anticipated in that zone. For example, if a property needs 20 square feet of mulch in a single zone then each subsequent zone must have 20 square feet of mulch as well.

  • Graywater must:

    • Be distributed subsurface or released to an area covered by a minimum of two inches of soil, bark, rock, or mulch.  

    • Be contained on the site where it is generated

    • Not runoff into streets and waterways

    • Not pond or pool on the soil surface

    • Not be stored

    • Not be used to irrigate lawns, root crops or edible parts of food crops that directly touch the soil

    • Not include a potable water connection or a pump
      (Note: The pump in a clothes washer is not considered part of the graywater system)

  • The site where graywater is used must be located in an area where seasonal high groundwater is at least five feet below ground surface. This will be verified by the district using available information prior to the application being provided.

Irrigation System Requirements

  • The graywater system must be located at least: 

    • Eighteen inches from any property line (Note: this minimum distance requirement shall be increased if the adjacent property is downhill from the graywater system);

    • Two feet from buildings;

    • Five feet from any septic tank; and 

    • One hundred feet from wells, waterways, or other water sources.

  • The irrigation system:

    • Must allow the user to direct the flow of graywater to the irrigation system or the sanitary sewer septic system using a brass diverter (3-way) valve. The diverter valve must be clearly labeled and easily accessible.

    • Shall be designed to prevent clogging of any emitters.

    • Shall be designed and installed to prevent contact with humans and pets.

  • Every 5-feet of exposed graywater piping shall be labeled "Caution: Nonpotable graywater, do not drink"

  • No overhead (spray) irrigation shall be connected to the graywater system.

  • Wastewater derived from specific activities that could create health issues must be diverted to the sanitary sewer or septic system using the required diverter (3-way) valve. These activities include, but are not limited to:

    • Washing diapers or similarly soiled garments;

    • Washing greasy or oily rags;

    • Cleaning car parts; and/or 

    • Disposing of waste solutions from activities that contain hazardous chemicals, such as photo labs.

  • The finished system must include an operating and maintenance manual. (An example manual may be provided upon request.) 

    • The manual shall include a diagram or schematic depicting where the graywater piping and outlets were installed relative to the home, washing machine, property lines, and the plants to be irrigated with graywater.

    • The manual is to remain with the building throughout the life of the system and indicate that upon change of ownership or occupancy, the new owner or occupant shall be notified that the structure contains a graywater system.

  • Notify the relevant enforcing agency (your local building, permitting, or planning departments) for additional rules to consider regarding the proposed location and installation of the graywater system, if they require you to do so.


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