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
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:
the discharge of pollutants to the “maximum extent
the appropriate water quality requirements of the
Water Act (CWA) and the Regional Water Quality Control Board’s (RWQCB)
Each SWMP has to address the following six
minimum control measures that are expected to result in
significant reductions of pollutants discharged into receiving
Public Education and Outreach
Illicit Discharge Detection and Elimination
Site Runoff Control
Post-Construction Runoff Control
Pollution Prevention/Good Housekeeping
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
Goal of Industrial Permit
minimize the potential of generating polluted storm water runoff.
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
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
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
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
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).