Clean Water Act National Enforcement Priorities

The current EPA water enforcement national priorities are to ensure Clean Water Act (CWA) compliance in the following wet weather areas:

Storm Water -- The 1987 Amendments to the CWA included the addition of paragraph (p) under Section 402 which established phased NPDES permit requirements for municipal and industrial storm water discharges. Storm water discharges are nationwide occurrences. The total number of storm water dischargers is unknown but expected to be several hundred thousand. Storm water run-off poses a significant threat to public health and the environment, and remains a leading cause of water quality impairment. Pollutants in storm water discharges can cause a variety of diseases in humans, ranging from dysentery to hepatitis. They can also contaminate fish, shellfish, and drinking water sources, create harmful algal blooms, and impair water quality.

Combined Sewer Overflows (CSOs) -- Pipes designed to convey both storm water runoff and sewage, are called combined sewers. Combined Sewer Overflow Systems were constructed prior to the development of sewage treatment plants and were intended to discharge sewage and storm water runoff directly to receiving waters. CSOs contain raw sewage and pose a significant public health concern. During rainfall, the capacity of combined sewer systems is exceeded and a mixture of storm water, household sewage and industrial wastewater overflows untreated through the old sewer outfalls. Most of the CSO communities are located in the Northeast, Great Lakes, and Northwest regions. Combined sewer systems serve roughly 900 communities containing about 40 million people. Most of the combined sewer systems were constructed 50 to 60 year ago.

Sanitary Sewer Overflows (SSOs) -- SSOs are overflows or releases from sanitary sewer systems and are illegal under the CWA. Municipal systems with separate sanitary sewers may have overflows due to inadequate capacity of the sewer lines and/or at the wastewater treatment plant, etc. SSOs pose a significant threat to public health and the environment, and remain a leading cause of water quality impairment. SSOs contain raw sewage and have high concentrations of bacteria from fecal contamination, as well as disease-causing pathogens and viruses. SSOs often occur in parks, backyards, city streets, playgrounds, and other areas that are frequented by the public, including children and pets. SSOs are occurring across the country, but are not consistently reported.

Concentrated Animal Feeding Operations (CAFOs) -- CAFOs are point sources subject to the NPDES program. A CAFO is a livestock facility, or lot, that confines a prescribed number of animals for at least 45 days out of a calendar year, and does not sustain crops on any portion of the facility or lot in the normal growing season. CAFOs exist in all regions of the U.S. They are concentrated in the eastern seaboard, the plains and the west coast. The total number of CAFOs is estimated to be in excess of 20,000.