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Stormwater Information


The State's Water Board has stringent new requirements on projects that will replace or add new impervious surfaces.  If your proposal will add or replace any outdoor impervious surfaces, please complete one of the attached stormwater checklists and attach it to your electronic building permit application:


  • Complete the Small Projects Form for individual single family home projects of any size, other projects that create and/or replace less than 10,000 square feet of impervious surface, and projects in the following categories that create and/or replace less than 5,000 square feet of impervious surface: restaurants, retail gasoline outlets, auto service facilities and parking lots (stand-alone or part of another use).
  • Complete the C.3 Regulated Projects Form for larger projects than those listed above, projects that will create or replace 5,000 sq ft or more of impermeable surface.

Attach it as a pdf to your electronic building permit application.  Note that the stormwater checklist is an initial screening form/worksheet and depending on your project, supplemental materials may also be required.


For further information refer to the county-wide guidance handbook C.3 Stormwater Technical Guidance, Version 3.2 (revised in January 2013 and formatted for double-sided printing).  It was designed to help developers, builders, and project sponsors include post-construction stormwater controls in their projects, in order to meet local municipal requirements that reduce the long term impacts of development on stormwater quality and creek channels.  For the C.3 regulations refer to the the California Regional Water Quality Control Board Municipal Regional Stormwater NPDES Permit.