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Sewer System Management Plan



The Sewer System Management Plan (SSMP) has been prepared in compliance with requirements of the San Francisco Bay Regional Water Quality Control Board (RWQCB) pursuant to Section 13267 of the California Water Code, and the State Water Resources Control Board (SWRCB) Order No. 2006-0003-DWQ.

The Sewer System Management Plan (SSMP) was adopted by City Council on February 4, 2013.


On July 7, 2005, the RWQCB issued a letter to the San Francisco Bay Region (Region 2) sewer collection system agencies, including the City of Mill Valley (City), that required the City to prepare an SSMP. At the same time, the RWQCB released an SSMP Development Guide that was prepared in cooperation with the Bay Area Clean Water Agencies (BACWA). The 2005 directive stated that the City must also comply with RWQCB sanitary sewer overflow (SSO) electronic reporting requirements issued in November 2004.

Similarly, on May 2, 2006, the State Water Resources Control Board (SWRCB) issued a directive through Order No. 2006-0003-DWQ to require all public wastewater collection system agencies in California with greater than one mile of sewers to be regulated under General Waste Discharge Requirements (Statewide WDR). The SWRCB action also mandates the development of an SSMP and the reporting of SSOs using an electronic reporting system. The SWRCB SSMP requirements are similar to those of the RWQCB but differ in organization and some details.

The intent of this SSMP is to meet the requirements of both the RWQCB and the Statewide WDR.

City of Mill Valley Service Area 

The City is located approximately 14 miles north of San Francisco, west of Richardson’s Bay in southern Marin County. The City is approximately 4.7 square miles in area, with approximately 13,900 residents, based on 2010 census data. The City’s sanitary sewer collection system service approximately 7,140 equivalent dwelling units (EDUs) through 59 miles of sewer pipes, two pumping stations and less than one mile of forcemain. Wastewater is conveyed to the Sewerage Agency of Southern Marin (SASM) wastewater treatment plant for treatment and discharge through a deepwater discharge to the San Francisco Bay.

The City conveys average dry weather flow of 1.1 million gallons per day (mgd) and peak wet weather flow of 13.3 mgd, as reported in the City’s Sewage Spill Reduction Action Plan, Volume III dated October 2010, which is available on the Public Works page of the City website, accessed through the url:

Mill Valley Wastewater Service Area Boundary and City Limits:

Mill Valley City Limits

To download the SSMP, please click on the links indicated below:

Sewer System Management Plan

SSMP Cover

SSMP Table to Contents

SSMP Sections 1-3

SSMP Sections 4-5

SSMP Section 6

SSMP Section 7

SSMP Section 8

SSMP Section 9

SSMP Sections 10-11

SSS Response Chain of Communication Chart

Organization Chart


Last updated: 6/18/2014 10:09:43 AM