Combine Sewer Overflows (CSO's)

Managing Risk to Water Quality

         Since the mid-1800s,cities have been constructed with sewer systems that carried both waste     water and storm water in the same pipe. Original designs were configured to carry all the wastes     and runoff to local streams, lakes, and rivers. By the 1950s, citizens and municipal authorities     recognized the need to separate these flows and began constructing waste water treatment     plants. As sewers were replaced, or when new ones were constructed, storm water collection was     confined to its own drainage system, and wastes were sent to the treatment plant.   

         Without proper monitoring and management, combined sewer overflows (CSOs) from existing     sewer systems pose a significant threat to communities where they are in place. Currently 40     million people in 900 communities nationwide (about 390,000 people in 56 counties in WV ) live     in areas with CSOs. CSOs contain untreated domestic waste and may contain commercial and     industrial wastes, surface runoff containing contaminant from various sources, and particulate     pollution in the air.

       Outbreaks of communicable diseases such as typhoid, cholera, dysentery and hepatitis

  have been traced to contaminated drinking water. Swimming and other water-contact

  recreation in areas affected by CSOs also can put you at risk, especially if you

  have cuts or scrapes where bacteria can enter the body.

        The EPA and WVDEP are taking steps to address hazards created by CSOs. In August 1989,    the EPA issued a national strategy for better managing CSOs. This strategy requires states to    identify all CSOs and categorize them according to their level of compliance with the Clean Water    Act requirements.

      The EPA has developed nine control measures to help reduce the effects CSOs have on water    quality. These measures include proper operation and regular maintenance programs for sewer    systems and CSO outfalls, maximizing collection systems for storage and minimizing the flow of    storm water into the CSO.

 Below is a map of Moundsville, WV with CSOs marked in read. You can click an overflow

 to link to a more site specific page.