What is Grey Water?

“Grey water” is untreated waste water. Examples of grey water includes water discharge from bathtubs, showers, bathroom washbasins, clothes washing machines, and laundry tubs. ‘Gently used’ water is considered safe to use by the Health and Safety Code Section 17922.12 criteria for irrigation purposes as long as it meets the following requirements:

  • There must be no contamination with toilet discharge or fecal matter.
  • It is absent of any infectious, contaminated, or unhealthy bodily wastes.
  • Does not present a threat from contamination by unhealthful processing, manufacturing, or operating wastes.

Benefits of Utilizing Grey Water

  • Reusing gently used water less fresh water can potentially lead to savings on the water bill.
  • More than 50% of the average household’s indoor water consumption is categorized as grey water.
  • Using ‘gently used’ indoor water for outdoor landscapes can reduce the fresh water usage.
  • There can be a reduction of water sent to the sewer or septic system.
  • Greywater can contain nutrients like phosphate and nitrogen that benefit plant growth.

For general information regarding the benefits of Grey Water and answers to the common questions on the topic, visit  Be Water Smart Greywater Information

If you are interested in installing a system, check out The City of San Francisco’s for outdoor irrigation manual link below.  It is a great resource guide that can inspire the type of design that is best for you.

No construction permit required if conditions in Section 1603A.1.1 are met
“Sacramento County has adopted the 2013 California Plumbing Code that does allow for graywater systems.  Plans and a plumbing permit are required.”

For a Building Permit information visit Sacramento County www.building.saccounty.net

Non-Permit ‘Laundry-To-Landscape’ Requirements (Section 1603A.1.1)

  • Gray water systems shall be designed to minimize contact with humans and domestic pets.
  • Water used to wash diapers or similarly soiled or infectious garments shall not be used and shall be diverted to the building sewer.
  • Gray water shall not contain hazardous chemicals.
  • An operation and maintenance manual shall be provided.
  • The gray water shall be contained on the site where it is generated.
  • Gray water shall be directed to and contained within an irrigation or disposal field.
  • Ponding or runoff is prohibited and shall be considered a nuisance.
  • Gray water 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.

What Does it Cost?

Clothes Washer Systems


$200-$300, homeowner installed

$1,000-$2,000, contractor installed




Simple and Complex System


Manufactured filter/reservoir units range from $4,000 for single irrigation line to $20,000 for multi-line applications

Plumbing fixtures, installation costs, permit costs, and design costs are involved in simple and complex systems.