San Mateo Countywide
Stormwater Pollution Prevention Program
555 County Center
Redwood City, CA  94063
tele: 650-599-1406
fax: 650-361-8227
Municipal contacts
Stormwater links
Best Management Practices
Integrated Pest Management
River of Words Poetry Contest
Community Action Grants
Mercury Recycling Information

Click here to visit the NEW San Mateo County STOPPP website -


What is STOPPP?

STOPPP is an acronym for the San Mateo Countywide STOrmwater Pollution Prevention Program.  The program is part of the National Pollutant Discharge Elimination System (NPDES) permit issued to the City/County Association of Governments (C/CAG), each incorporated city and town in the county, and the County of San Mateo.  C/CAG-STOPPP offices are in Redwood City, California.

 Why does STOPPP exist?

A variety of toxic pollutants are washed from streets and parking lots into storm drains, creeks, and ultimately the Bay or ocean.  These pollutants include leaking oil, antifreeze, and gasoline from motor vehicles; copper dust, which is released from motor vehicle brake pad linings; rubber tire dust which wears off motor vehicle tires;  soaps and chemicals used to wash motor vehicles; waste motor oil from vehicles, lawn mowers, and small equipment which isn't taken to a recycling center; oils from leaking trash containers at restaurants; and fertilizers, pesticides, & herbicides when used excessively on lawns or gardens.  Recent studies indicate that many of the pollutants entering the San Francisco Bay come from polluted stormwater runoff.  The Federal Clean Water Act and the California Porter-Cologne Water Quality Control Act require that large urban areas discharging stormwater into the San Francisco Bay or the Pacific Ocean have an NPDES stormwater discharge permit.  San Mateo, Santa Clara, Alameda, Marin, and Contra Costa Counties have each obtained these permits.   Certain types of businesses must also apply for individual coverage, by filing a Notice of Intent (NOI) with the State Water Resources Control Board..

What is the goal of STOPPP

The purpose of these NPDES permits and the goal of STOPPP is to reduce discharge of pollutants to creeks, the Bay and ocean to the maximum extent practicable.

How is STOPPP being implemented?

The conditions of the NPDES permit are being met through the accomplishment of tasks.  Tasks are either assigned to the countywide General Program or to individual municipal programs.  Local municipal governments are assigned tasks that include inspecting the storm drain system, street sweeping, and educating/inspecting commercial facilities.  Commercial and industrial businesses are encouraged to implement Best Management Practices (BMPs), which eliminate or reduce the discharge of pollutants to the storm drain system.

 What will STOPPP do for me?

Through the success of the city and county stormwater programs in the Bay area, the water quality of the Bay will improve.  With improved water quality, the marine ecosystem will become healthier.  A healthier marine ecosystem will enhance the quality of life for all residents around the Bay and on the ocean.

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