Storm Water

The Imperial County Department of Public Works (ICDPW) is responsible for Storm Water program implementation and oversight of projects within County right of way that may be subject to storm water requirements.

Storm Water is water that originates during precipitation events and when snow/ice melt. Storm water can soak into the soil (infiltrate), be held on the surface and evaporate, or runoff and end up in nearby streams, rivers, or other water bodies (surface water).

Imperial County is subject to regulation by the California State Water Resources Control Board (Water Board) under National Pollutant Discharge Elimination System (NPDES) General Permit and Waste Discharge Requirements (WDRs) for Small Municipal Separate Storm Sewer Systems (MS4s) Order No. 2013-0001-DWQ. The Phase II MS4 Permit that became effective in July 2013 replaced the previous order in effect since April 2003.

The Phase II MS4 Permit is a General Permit issued by the Water Board pursuant to section 402 of the federal Clean Water Act and implementing regulations (Code of Federal Regulations Title 40, Part 122) adopted by the United States Environmental Protection Agency (EPA), and Chapter 5.5, Division 7 of the California Water Code. These regulations apply to point discharges from MS4s to waters of the state for which the County owns and operates.

The County of Imperial established legal authority to implement the requirements of the order through adoption of Ordinance No. 1508 on August 25, 2015, Minute Order No. 31.

Order No. 2013-0001-DWQ, NPDES No. CAS000004

General Permit for Waste Discharge Requirements (WDRs) for Storm Water Discharges from Small Municipal Separate Storm Sewer Systems (MS4s)

Imperial County Ordinance No. 1508

Requirments for Storm Water Control - Title 9, Division 31, Chapters 1 through 7