Graywater Systems

Gflow Graywater

Graywater is untreated wastewater from bathroom sinks, bathtubs, showers and clothes washers but does not include wastewater from toilets, kitchen sinks or dishwashers. A graywater system is a type of onsite wastewater treatment system that utilizes trenches, subsurface drip irrigation systems, and mulch basins for wastewater disposal but can have the added benefit of using the wastewater as a subsurface irrigation source. A Clothes Washer System, which only utilizes graywater from a single clothes washer, can be installed without a permit, provided the system is installed in accordance with the Graywater System Requirements for a Single Clothes Washer. Larger graywater systems, which require more extensive plumbing modifications, require a permit. For more information on graywater systems, please see the Graywater Systems for Outdoor Irrigation Design and Procedures Manual.

The County of San Diego oversees graywater systems for the unicorporated areas of the County only. For incorporated areas (cities), please see the respective city for graywater requirements. The purpose of regulating the design, installation and maintenance of graywater systems is to prevent public and environmental health nuisance conditions caused by improper installation or maintenance. The goals of the program are:

  • Ensure that graywater systems can operate in all weather conditions with minimal maintenance
  • Prevent the contamination of surface water and groundwater from improperly designed or operated graywater systems
  • Prevent human and animal contact with graywater effluent
  • Provide public guidance on the design, installation and operation of graywater systems 

Program Services | Contact Us | Useful Information


Program Services

Useful Information

Chapter 16A CPC Graywater Regulations

Graywater Frequently Asked Questions


Groundwater Separation Requirements

Percolation Test Form

San Diego County Code: Onsite Wastewater System Ordinance