Storm water carries polluted runoff from streets, rooftops, parking lots, industrial
facilities and construction sites into water bodies. This major source of
pollution has attracted much more attention lately, and controlling stormwater
pollution is critical to improving and maintaining water quality in the most
populated areas and rapidly developing areas of the country.

The 1987 Amendments to the Clean Water Act set the process of controlling stormwater
pollution into motion. The changes were developed and instituted in two phases.

In the early 1990s, "Phase I" required cities with populations over 100,000, industrial facilities, and construction sites five acres or greater in size to obtain a NPDES permit. These regulations, which depended primarily on stormwater management plans, have
driven major urban stormwater control programs in the largest cities during the
past decade.

In 2003, "Phase II" regulations kicked in, which required all communities within "urbanized areas" with at least 50,000 people to apply for a NPDES stormwater permit. "Urbanized areas" were determined by population and density (based on the 2000 census), and they
include some communities that are much smaller than 50,000 people. In addition,
Phase II requires permits for any construction activity that disturbs one acre
or greater, and it has significantly expanded the number of industrial categories that can claim exemption from stormwater regulations.

Are stormwater programs the same from state-to-state?

The EPA has set some minimum federal requirements for all municipal, industrial and
construction stormwater pollution permits and programs. However, these
requirements do not include technology- based effluent limits similar to those
that are in municipal and industrial wastewater discharge permits. Instead, they rely a) on stormwater management plans to identify best management practices that will reduce
stormwater pollution and b) full implementation and monitoring of those practices.

Without specific, required limits, state permits vary widely across the country. States
may impose stricter rules and tighter timetables for compliance, and some
states have. For example, California, Washington, Vermont and Oregon are all moving
their municipal and industrial stormwater permitting programs ahead thanks to
citizen action. Wisconsin included specific limits in its draft construction stormwater permit, but the permitting agency is unsure whether and how they will be met. Michigan
and Oregon have issued permits that require watershed-based coordination for controlling
stormwater pollution.

Who must get a stormwater pollution control permit?

Stormwater permits are required for two major categories of stormwater pollution: municipal and industrial. Within each category are several distinctions. Municipal
stormwater permits are broken down by population. Large and medium cities were required to manage their stormwater in the early to mid-1990s. In March 2003, smaller urbanized areas were incorporated into the stormwater program.

Industrial activity is broken down into eleven categories. Construction activity is one of those categories. It warrants particular attention because separate NPDES permits are required for construction sites one acre or greater to control erosion and sedimentation.

Learn more about municipal storm water permits

Learn more about industrial storm water permits

Learn more about construction storm water permits