In 1994 the United States Environmental Protection Agency published new regulations for communities and sewage treatment plants that have sewer lines that take in sanitary sewage and storm water. In the Kiski Valley area there were 31 combined sewer outfalls. These outfalls discharged rain water and sewage to the Kiski River during moderate to severe wet weather events.
The Kiski Authority was required by the PA Department of Environmental Protection to prepare a long Range CSO (Combined Sewer Overflow) Control Plan. The Authority selected the EPA CSO Control Policy "presumption" approach criteria ii through their Long Term Control Plan (LTCP) requiring elimination or capture for treatment of no less than 85% by volume of combined sewage collected in the CSS (Combined Sewer System) during precipitation events. Through sewer separation and upgrade projects in tributary communities the number of diversion outfalls has been reduced to two (2) currently thus increasing the volume of collected sewage and reducing the volume of stormwater treated at the treatment plant. Additionally, the Plant Expansion Project has provided the necessary additional capacity to meet the EPA requirements.