Placer County is subject to the mandates for stormwater discharges as part of the Small Municipal Separate Storm Sewer Systems (MS4), Phase II of the National Pollution Discharge Elimination System (NPDES) small municipal stormwater program (State General Permit Number CAS0000004 (PDF)).
This program, which is part of the Federal Clean Water Act, requires the County to regulate all projects that create and/or replace more than 2,500 square feet of impervious surface.
The goal of the West and East Placer Design Manuals is to provide standards for conformance to the permit requirements. The Design Manuals also provide hydro-modification management standards. In addition, the West Placer Design Manual achieves the objectives of the Placer County Conservation Plan (PCCP).
The West and East Placer Storm Water Quality Design Manuals are available for download below.