Greywater System Guidelines

Laundry to Landscape Greywater System Guidelines

These guidelines summarize the State of California’s regulations for greywater.  For detailed guidelines visit: Section 1602.1.1 of Chapter 16 of the California Plumbing Code


Landscape Requirements

  • All greywater must be distributed from the washing machine to a landscape area that is large enough to absorb the greywater 
  • Greywater must: 
    • Be distributed subsurface or released to an area covered by a minimum of two inches of mulch or rock.  
    • Be contained on the property where it is generated 
    • Not runoff into streets and waterways 
    • Not pond or pool on the soil surface 
  • Greywater System shall: 
    • Not be used to irrigate lawns, root crops or edible parts of food crops that directly touch the soil 
    • Not be interconnected with the potable water system
    • Not include a pump other than the pump that is in the clothes washer
  • The site where greywater is used should be located in an area where seasonal high groundwater is at least five feet below ground surface. 
  • The finished system must include an operating and maintenance manual. 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 greywater system. 

Irrigation System Requirements

  • The greywater system must be located at least: 
    • Eighteen inches from any property line or more if the adjacent property is downhill; 
    • 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 greywater 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. 
  • No overhead (spray) irrigation shall be connected to the greywater 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.