Stormwater Awareness


Most storm water discharges are considered point sources and require coverage by a National Pollution Discharge Elimination System (NPDES) permit.  There are three types of regulated storm water discharges that require permit coverage:

Municipal Separate Storm Sewer Systems (MS4)

School districts, along with most municipalities, are required to obtain a NPDES permit under this plan. It requires each district to develop and implement a Storm Water Management Plan (SWMP) to:

  • Reduce the discharge of pollutants to the “maximum extent possible” 

  • Protect water quality

  • Satisfy the appropriate water quality requirements of the Clean Water Act  (CWA) and the Regional Water Quality Control Board’s (RWQCB) plan.  

Each SWMP has to address the following six minimum control measures that are expected  to result in significant reductions of pollutants discharged into receiving water bodies.

  • Public Education and Outreach

  • Public Participation/Involvement

  • Illicit Discharge Detection and Elimination

  • Construction Site Runoff Control

  • Post-Construction Runoff Control

  • Pollution Prevention/Good Housekeeping

Industrial Activities


Industrial facility activities, such as material handling, usage, and storage are often exposed to the weather. As storm water runoff comes into contact with these materials, it picks up the pollutants and transports them to nearby storm sewer systems, rivers, lakes, or coastal waters.

Goal of Industrial Permit

  • To minimize the potential of generating polluted storm water runoff.

  • School districts with transportation facilities are required to develop and implement a Storm Water Pollution Prevention Plan (SWPPP) for their onsite industrial activities (vehicle washing, parking, maintenance, and fueling).

  • Implementation of Best Management Practices (BMPs) will decrease the potential of polluted runoff generated by site activities.

Construction Activities


Storm water runoff from construction activities can have a significant impact on water quality. As storm water flows over a construction site, it picks up pollutants like sediment, debris, and chemicals. Polluted storm water runoff can harm or kill fish and other wildlife. Sedimentation can destroy aquatic habitat and high volumes of runoff can cause stream bank erosion.

  • The NPDES Storm Water program requires operators of construction sites of one acre or larger (including smaller sites that are part of a larger common plan of development) to obtain authorization to discharge storm water under an NPDES construction storm water permit.

  • The development and implementation of storm water pollution prevention plans is the focus of NPDES storm water permits for regulated construction activities. 

Goal of Construction Permit

To protect the quality and beneficial uses of the Nation's surface water resources from pollution in storm water runoff from construction activities.

  • Permit requires operators to plan and implement appropriate pollution prevention and control practices for storm water runoff during the construction period.

  • These Best Management Practices (BMPs) are aimed primarily at controlling erosion and sediment transport. Additional controls are aimed at other pollutants such as construction chemicals and solid waste (e.g., litter).