Sewer System Management Plan (SSMP)

The District maintains approximately 199 miles of mainline and trunk line sewers and 7.3 miles of force main pipe. In addition, the District owns and operates five major pump stations, and 14 minor pump stations and lift stations. The major pump stations collect and pump flow from the minor stations and trunk lines to the Central Marin Sanitation Agency (CMSA) treatment plant.  Sewer laterals - both lower and upper laterals, - are owned and maintained by individual private property owners.

The State Water Resources Control Board (SWRCB) has issued Statewide Waste Discharge Requirements for sanitary sewer systems, which include requirements for development of a Sewer System Management Plan (SSMP). 

The SWRCB requirements for SSMP’s are outlined in the Statewide General Waste Discharge Requirements for Sanitary Sewer Systems, dated December 6, 2022 (SSSWDR) Order No. 2022-0103-DWQ. The District's SSMP was adopted by the Board on June 18, 2025, and is organized by the SWRCB outline and contains 11 elements. The structure of this document follows the section numbering and nomenclature specified in the SSSWDR SSMP requirements. The SSMP refers to supporting plans, codes, ordinances, and documents, which are included in the links below.