California Laws on Septic Tanks

By Ruchika Sachdeva

A properly used septic tank system works to remove bacteria and viruses, allowing soluble matter--which is not degradable--to reach ground water. This pollutes ground water and reduces the quality of ground and nearby surface water. In July 2010, the government of California implemented new regulations for septic tank systems or On-Site Wastewater Treatment Systems (OWTS). The California State Water Resources Control Board (CSWRCB) proposed the new regulations to shield groundwater and surface water quality from waste-water discharge. The new regulations stem from the passage in 2000 of AB 885, which can be accessed at

Regulations for Existing Septic Systems

According to the new regulations, owners of existing septic systems must get their septic tanks inspected for solid accumulations once every five years by a qualified service provider. The inspection will cost about $325. And documentation must be maintained to show that owners are following the regulations. Existing septic systems within 600 feet of an impaired water body--a surface water body that does not meet water-quality standards--are subject to special regulations.

Special Requirements for Septic Systems within 600 Feet of an Impaired Water Body

In areas where the Regional Water Board finds that the septic systems are polluting specific water bodies; septic systems within 600 feet of impaired surface water body will be required to have a qualified professional determine if the system is contributing to polluting the water body. And if so, then the septic system will have to be retrofitted with additional treatment systems, which could cost approximately $45,000.

Regulations for New Septic Systems

In addition to the regulations applicable to the existing septic systems, new systems are subject to certain other regulations. A site assessment and design has to be performed by a qualified professional for all new septic systems before construction. All new systems must also be determined for seasonal high groundwater.

New systems can only be constructed by a State licensed contractor or the property owner. All new systems must have filters that retain solids bigger than 3/16 inches in diameter and should be designed to maximize soil treatment. For conventional septic systems, a minimum depth to groundwater or impermeable layer of three feet should be maintained. Systems with additional treatment should have a minimum two-feet depth.

Pump using new systems must be equipped with malfunction alarms and have an emergency tank capacity to store waste for up to 24 hours.

All new systems must have an operation and maintenance manual that must be provided to all subsequent property owners.

In areas where existing septic systems have been identified to be contributing to pollution of a surface water body, new septic systems within 600 feet of an impaired surface water body must have an additional treatment system, which can cost approximately $35,000 for installation.

About the Author

Based in Los Angeles, Ruchika Sachdeva is a versatile writer. She has been writing, professionally since 2004. Sachdeva has written for several nonprofits like and She has a under-graduate degree in English literature from the University of Delhi, India and a graduate degree in development communication from Anwar Jamal Kidwai Mass Communication Research Center, Jamia Millia Islamia in New Delhi, India.

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