Septic Systems

Community Development Agency

Onsite Wastewater Treatment Systems aka Septic Systems

If you have any questions regarding septic systems please call our office (415) 473-6907 to speak with one of our inspectors.

Onsite Wastewater Treatment Systems (OWTS) commonly referred to as septic systems should be managed to protect the public from disease and to protect ground and surface water resources from contamination. The primary function of an OWTS is to treat, reduce, or eliminate contaminants to reduce the threat to public health and the environment.

There are two categories of OWTS – ‘Standard’ and ‘Alternative’ technology systems. A permit and approval from EHS must be obtained before the construction, repair, replacement, or modification of an OWTS.

To learn about constructing, operating, and maintaining a graywater system, please visit the Graywater Systems section of our website. If you have further questions, please call us at (415) 473-6907.


OWTS Applications, Processes and Fees

Sewage disposal is required for any home or structure inhabited by people. Onsite sewage disposal systems (OWTS) provide sewage disposal for homes/structures located in areas that do not have community sewer systems.

Incorrectly installed OWTS can harm water quality and put people at risk.  

The location and construction of OWTS must be approved and permitted by the County of Marin EHS. Therefore, prior to building a home or structure dependent on an OWTS, EHS approval and an OWTS permit is required prior to the issuance of a building permit. The permit process includes a site review and percolation tests documented by EHS. An EHS OWTS permit is also required for any repairs, modifications, or replacements to a system.

The information below contains specific information related to site review and various OWTS permits. If you have questions or need further information, please call (415) 473-6907 or come by our office for assistance.


  • Application for site review, construct and operate an OWTS (or repair; replace), construct an alternative system, tank abandonment, minor modification, office/field consultation.

Procedures for Abandonment of Septic Tank after Issuance of Permit


OWTS Laws, Regulations and Policies

Marin County Regulations

State of California Regulations

AB885 – Water Quality Control Policy for Siting, Design, Operation, and Maintenance of Onsite Wastewater Treatment Systems

To determine if a property is within 600 feet of a 303(d) federal listed impaired water body, the address can be entered at OWTS Map. The map is a helpful tool to determine proximity to a water body. A more precise measurement may be required to verify the actual distance to the water body.

On September 27, 2000, Governor Gray Davis signed into law, Assembly Bill 885 that required the State Water Resources Control Board (SWRCB) to adopt standards or regulations for the permitting and operation of onsite waste water systems (OWTS). On June 19, 2012, the State Water Resources Control Board (SWRCB) approved Resolution No. 2012-0032, adopting the Water Quality Control Policy for Siting, Design, Operation, and Maintenance of Onsite Wastewater Treatment Systems (OWTS Policy). This Policy establishes a statewide, risk-based, tiered approach for the regulation and management of OWTS installations, repairs, replacements, and modifications, and sets the level of performance and protection expected from OWTS.

If the current OWTS (septic system) is functioning properly and wastewater is not surfacing, there are no immediate impacts to property owner. Even if the OWTS is malfunctioning, the Policy may not affect the property owners. Only properties that are within 600 feet of a federally-listed impaired water body (303d) will have different requirements (Tier 3) for repairs, replacement, modifications, or new OWTS. (See Tier 3 described in #9.) Properties within the county and not within 600ft to an impaired water body will only be subject to current county regulations and policies.


Performance Evaluation Guidelines

The guidelines purpose of a performance evaluation is to determine whether an existing septic system is functional and meets minimum standards of performance established by the San Francisco Regional Water Quality Control Board (RWQCB) and the County of Marin, Environmental Health Services (EHS). Please review the Performance Evaluation Guidelines which describe information on conducting a hydraulic load and dye test.

Alternative OWTS Program and Monitoring

The current Residential Operating Permit program requires all alternative systems be monitored at a specified frequency by a qualified professional or County staff. A report documenting the inspection and applicable maintenance performed is submitted. EHS staff is required by the Bay Area Regional Water Quality Control Board (RWQCB) to submit an annual report based on information received in the professionals’ reports.

The operating permit fee charged by EHS, accounts for staff time administering the program; managing records and files; inspecting of a number of alternative systems throughout the year; reviewing the monitoring reports; compiling data and entering it into a database; authoring the annual report for the RWQCB; notifying owners of overdue reports; pursuing compliance; alerting owners to needed corrective action when problems arise with their system; answering owners questions by phone and email; interacting on a regular basis with septic professionals; updating property owner information; and sending out billing notices.



EHS Septic Program Fee Schedule - A technology fee surcharge of $10 will be assessed on most permits separately from the permit fee in order to offset County costs associated with the permit tracking system.

Policy and Information Related to OTWS and County Building Permits

  • Remodel and Additions Policy - This policy provides guidance for property owners who wish to improve, remodel, or add on to residences which are served by onsite wastewater systems.

Pumper Vehicles and Chemical Toilet Distribution

If you distribute chemical toilets, or haul and dispose of solid waste from septic tanks and portable toilets, you must be registered by EHS, and renew your license each year.

To apply for a registration complete the application and submit to EHS with the current fee.


EHS Septic Program Fee Schedule - A technology fee surcharge of $10 will be assessed on most permits separate from the permit fee in order to offset County costs associated with the permit tracking system.

Maintenance Tips and Additional Information

Proper maintenance of an OWTS is important to keep your system running smoothly and to potentially save money on repairs. The National Environmental Services Center provides a booklet as a guideline for homeowners and includes maintenance tips, do’s and don’t’s, and a brief explanation as to how an OTWS works.

Frequently Asked Questions

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