Pursuant to the authority granted by the Clean Water Act (formerly known as the Federal Water Pollution Control Act), the National Pollutant Discharge Elimination System (NPDES) permit program controls water pollution in the United States by regulating the sources that discharge pollutants.

 

Under federal regulations set forth by the U.S. Environmental Protection Agency (EPA), entities releasing "point source pollutants" into domestic waters must first obtain an NPDES permit. A "point source pollutant" is one that emanates from a distinct and specific source (such as a well or pipe), as opposed to a pollutant for which the exact source of the pollution is not as ascertainable.

 

Storm water runoff from construction activities has the potential to significantly affect the quality of the nation's waters. As storm water runs through the site of a construction project, it gathers debris, sediment, chemicals and other pollutants. Construction waste may then reach creeks, streams, lakes and other bodies of water, causing serious harm to many species of wildlife and their habitats. In addition, large volumes of storm water runoff may eventually contribute to the erosion of embankments along the water's edge.

 

Accordingly, the EPA has enacted two sets of federal storm water regulations. In general terms, the first set of regulations affects all operators of construction sites five acres or larger. The second set of regulations generally affects smaller construction projects.

 

In 1990, the EPA enacted the first set of federal storm water regulations ("Phase I"). The Phase I regulations identify 11 categories of industrial activity (including construction activity) that are required to obtain an NPDES permit. Under these regulations, all operators of construction activity disturbing five or more acres of land must apply for an NPDES storm water permit. As used by the EPA, "disturbance" refers to the exposure of soil resulting from activities such as clearing, excavating and grading.

 

Phase I regulations also require operators of sites disturbing less than five acres to obtain an NPDES permit, if their activity is part of a "larger common plan of development or sale" with a planned disturbance of five acres or greater. The EPA defines "larger common plan of development or sale" as a "contiguous area where multiple separate and distinct construction activities are occurring under one plan." To illustrate, the EPA cites the example of an operator building on three half-acre lots in a six-acre development.

 

In response to concerns that smaller construction projects similarly posed a risk of environmental harm to domestic waters, the EPA put a second set of storm water regulations into effect ("Phase II"). Effective in March 2003, the Phase II regulations extended coverage to construction site activities that result in a land disturbance of equal to or greater than one acre and less than five acres. Operators of construction activities that disturb less than one acre must also obtain an NPDES permit, if the activities are part of a "larger common plan of development or sale" with a planned disturbance of equal to or greater than one acre and less than five acres.

NPDES permits may also be required for sites less than one acre if the NPDES permitting authority (the EPA or state or local environmental agencies, depending upon location) determines that the construction activities conducted there pose a significant risk to local waters.