Office of Energy and Sustainable Development
Office of Energy and Sustainable Development

Graywater Clothes Washer System: Laundry to Landscape

Clothes Washer System:  Washing machine systems are the least complicated type of graywater system.  They are great for gardens with minimal irrigation needs, are low-cost, easy to install, and require very little maintenance.   No permit is required for a clothes washing machine, providing all system design and code requirements are met as outlined in Chapter 16A of the 2007 California Plumbing Code  Permits are required for systems that include tanks or pumps. 

Designing a Clothes Washer System:

  • Attach washing machine discharge hose to either a 3-way valve to switch between a graywater system and the sewer or a second standpipe.  Graywater must be capable of being reconnected to the sewer.
  • Graywater then travels out to the garden.  A mulch basin with 2” cover is the simplest system for distribution and irrigation. Clearly label flow direction to sewer or yard. Once outside the building, the discharge must drain directly to the disposal field by hose or pipe.
  • Piping at five foot increments & at hose connection point is to be permanently labeled: “CAUTION: NONPOTABLE WATER, DO NOT DRINK”.
  • All graywater must be used the same day it was produced.

Clothes Washer System Requirements from 2007 California Plumbing  (see California Plumbing Code):  The text below is taken from the 2007 California Plumbing Code Chapter 16A.  No permit is required for a clothes washer graywater system providing all system design and code requirements are met as outlined below.  Proper system design, maintenance and use are the responsibility of the system owner, not the City of Berkeley. 

  1. Registration of your system with the City of Berkeley Building Department is not required.
  2. The design shall allow the user to direct the flow either to the irrigation or disposal field or the building sewer. The direction control of the graywater shall be clearly labeled and readily accessible to the user.
  3. The installation, change, alteration or repair of the system does not include a potable water connection or a pump and does not affect other building, plumbing, electrical or mechanical components including structural features, egress, fire-life safety, sanitation, potable water supply piping or accessibility.
    Note: The pump in a clothes washer shall not be considered part of the graywater system.
  4. The graywater shall be contained on the site where it is generated.
  5. Graywater shall be directed to and contained within an irrigation, mulch basin, or disposal field.
  6. Ponding or runoff is prohibited, and shall be considered a nuisance.
  7. Graywater may be released above the ground surface provided at least two (2) inches (51mm) of mulch, rock or soil or a solid shield covers the release point.  Other methods which provide equivalent separation are also acceptable.
  8. Graywater systems shall be designed to minimize contact with humans and domestic pets.
  9. Water used to wash diapers or similarly soiled or infectious garments shall not be used and shall be diverted to the building sewer.
  10. Graywater shall not contain hazardous chemicals derived from activities such as cleaning car parts, washing greasy or oily rags or disposing of waste solution form home photo labs or similar hobbyist or home occupational activities.
  11. Exemption from construction permit requirements of this code shall not be deemed to grant authorization for any graywater system to be installed in a manner that violates other provisions of this code or any other laws or ordinances of the City of Berkeley.
  12. All systems shall have a 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 tenant shall be notified that the structure contains a graywater system.

Proper system design, maintenance and use are the responsibility of the system owner, not the City of Berkeley.

Links and Resources:

City of Berkeley Graywater Collection Systems

California Plumbing Code Graywater Chapter 16A 

East Bay Municipal Utility District (EBMUD) 

Nonprofit organization focusing on policy, trainings and best practices Greywater Alliance

Learn how to green your home, check out other City of Berkeley Green Permit Guides 

Back to Office of Energy and Sustainable Development Homepage

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