County's Drainage Policy

In addition to NPDES requirements, all projects resulting in an increase in impervious surface must also comply with the County's Drainage Policy.

The San Mateo Water Pollution Prevention Program (SMCWPPP) is a partnership of the City/County Association of Governments (C/CAG), each incorporated city and town in the county, and the County of San Mateo, which share a common National Pollutant Discharge Elimination System (NPDES) permit.

The SMCWPPP program makes a variety of resources available on its website http://www.flowstobay.org/ which are applicable to new development on a county-wide level. This website provides both specific resources applicable to the processing of development permits within the unincorporated areas of the County, as well as links to resources produced at the county-wide level, in order to inform contractors and home owners about NPDES requirements.

C.3 and C.6 Development Review Checklist

The C.3 and C.6 Development Review Checklist Captures a formal calculation of existing, new and replaced impervious surface at the project site. The completed form is required for all projects requiring a Planning or Building permit that result in over 1,000 square feet of inpervious surface and is required to be submitted at the time of permit application. If the project involves the development if more than one property at a time within properties owned by a common property owner one form shall be completed for all properties involved in development.

Provision C.3.i Small Projects

New stormwater requirements became effective on December 1, 2012 for development projects that will create and/or replace at least 2,500 square feet of impervious, but less than 10,000 square feet of impervious surface, and standalone single family homes that create and/or replace 2,500 square feet or more of impervious surface.