National Pollutant Discharge Elimination System (NPDES)

Under the Clean Water Act, the NPDES permit program controls water pollution by "regulating point sources that discharge pollutants into waters of the United States" (1).  Introduced in 1972, the NPDES permit program has contributed significantly to improving the water quality in the U.S. (1).

While the NPDES permit program has been successful in its own right, there has been an increasing transition to a form of Total Maximum Daily Load (TMDL) to assure water quality through the NPDES permit program.  A TMDL is a "calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards, and an allocation of that amount to the pollutant's sources" (2)


It is important to note that "while TMDLs have been required by the Clean Water Act since 1972, until recently states, territories, authorized tribes, and EPA have not developed many. Several years ago citizen organizations began bringing legal actions against EPA seeking the listing of waters and development of TMDLs. To date, there have been about 40 legal actions in 38 states. EPA is under court order or consent decrees in many states to ensure that TMDLs are established, either by the state or by EPA" (2).

Thus, one is able to see that the NPDES permit program under the authorization of the Clean Water Act, is an evolving piece of policy (much like any other piece of public policy).


Sources:

1: http://cfpub.epa.gov/npdes/index.cfm

2. http://www.ririvers.org/wsp/CLASS_2/TMDL.htm