Gray water for Irrigation: Code, Permitting, and Systems
What is Gray Water?
Pursuant to Health and Safety Code Section 17922.12, “gray water” means untreated waste water that
– has not been contaminated by any toilet discharge,
– has not been affected by infectious, contaminated, or unhealthy bodily wastes, and
– does not present a threat from contamination by unhealthful processing, manufacturing, or operating wastes.
“Gray water” includes but is not limited to waste water from bathtubs, showers, bathroom washbasins, clothes washing machines, and laundry tubs, but does not include waste water from kitchen sinks or dishwashers.
Plumbing Code and Permits
Non-Permit Clothes Washer Requirements
- 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