Marin County Public Works Department manages the Flood Control and Water Conservation District. San Anselmo and the rest of the Ross Valley/Corte Madera Creek watershed is within Flood Zone 9. A special fee, which was approved by a property owner election in 2007, generates revenue to pay for flood control projects. Flood Zone 9 is overseen by an Advisory Board, but all major actions require authorization by the Board of Supervisors of the Flood Control District. San Anselmo's representative to the Flood Zone 9 Advisory Board is Councilmember Tom McInerney.
Flood Zone 9 performs many functions including:
The cleaning and maintenance of creeks
Development of a capital improvement plan guiding flood mitigation activities
The construction, operation and maintenance of levees, pumping stations, culverts and drainage ways
Applying for and matching grant funding for replacement of bridges and buildings contributing to flooding