The Storm Water Program in the
Los Angeles Region


Storm water is defined by US EPA as the runoff generated when precipitation from rain and snowmelt events flows over land or impervious surfaces without percolating into the ground. As it flows, storm water runoff collects and transports pollutants to surface waters. Some of these pollutants are visible such as sediment, motor oil and trash, as well as pollutants that are not easily visible such as dissolved metals, nutrients, oxygen demanding substances, and organic chemicals.

Although the amount of pollutants from a single residential, commercial, industrial or construction site may seem unimportant, the combined concentrations of contaminants threaten our lakes, rivers, wetlands and other water bodies. Pollution conveyed by storm water degrades the quality of drinking water, damages fisheries and habitat of plants and animals that depend on clean water for survival. Pollutants carried by storm water can also affect recreational uses of water bodies by making them unsafe for wading, swimming, boating and fishing. In most cases, storm water flows directly to water bodies through separate storm sewer systems, contributing a major source of pollution to rivers, lakes, and the ocean.

Storm water discharges in California are regulated through National Pollutant Discharge Elimination System (NPDES) permits. However, storm water may also act as a resource and recharge groundwater when properly managed. The Water Boards are actively involved in initiatives to improve the management of storm water as a resource.

In the Los Angeles region, the storm water program is a comprehensive program to manage the quality of discharges from the municipal separate storm sewer system in the incorporated and unincorporated areas in Los Angeles, and Ventura counties, the discharges from the 10 categories of industries listed in the Federal Regulations (40 CFR 122.26), and the discharges from construction sites with land disturbance of 1 acre or more.


  • Nutrients such as phosphorus and nitrogen can promote the overgrowth of algae, deplete oxygen in the waterway and be harmful to other aquatic life.
  • Bacteria from animal wastes and illicit connections to storm sewer systems can make nearby lakes and bays unsafe for wading, swimming and the propagation of edible shellfish.
  • Oil and grease from automobiles causes sheen and odor and makes transfer of oxygen difficult for aquatic organisms.
  • Sediment from construction activities clouds waterways and interferes with the habitat of living things that depend upon those waters.
  • Careless application of pesticides, herbicides and fertilizers affect the health of living organisms and cause ecosystem imbalances.
  • Litter damages aquatic life, introduces chemical pollution, and diminishes the beauty of our waterways.
  • Heavy metals and organic chemicals from industrial facilities can cause toxicity in the aquatic life that use our waterways.
The best way to control contamination to storm water is usually at the source, where the contaminants can be identified, reduced or contained before being conveyed to surface water. More often than not, it's more expensive and difficult to remove the combination of contaminants that are present at the end-of-pipe where storm water is finally discharged directly to a receiving waterbody. Employing best management practices, or "BMPs" to prevent contamination of storm water is key. Proper storage of chemicals, good housekeeping and just plain paying attention to what's happening during runoff events can lead to relatively inexpensive ways of preventing pollutants from getting into the runoff in the first place and then our waterways.
If you are required to obtain coverage under either the Industrial General Permit or the Construction General Permit and you have not obtained coverage, do so right away. Please visit the Industrial Storm Water Program page or the Construction Storm Water Program page for information on how to apply for coverage. Municipalities with questions about compliance, please visit the Municipal Storm Water Program page for information. If you already have coverage under either the Industrial General Permit or the Construction General Permit, it is your obligation to comply with the requirements in these permits. Please see the Industrial and Construction Storm Water Program pages for the details on the requirements. You can also report a facility or a construction site that does not have storm water permit coverage. These non-filers have an undue financial advantage over the industrial facilities and construction sites that comply with the regulations.

Recent News:

  • Renewal of the Industrial General Permit is underway - the public comment period was extended for the proposed Industrial General Permit amendment.
  • Proposed Industrial General Permit Amendment. Link to Proposed Amendment
  • The deadline to submit the Annual Report for the Industrial General Permit is July 15. Guide for Submittal
  • The deadline to submit the Annual Report for the Construction General Permit is September 1.
  • The annual fee for a No Exposure Certification is $150.
  • The deadline to recertify No Exposure Certifications is October 1. Guide for recertification

STORM WATER PROGRAM CONTACTS: