Illustration of a <a href="https://en.wikipedia.org/wiki/combined_sewer" class="extiw" title="w:combined sewer">combined sewer</a> system.
U.S. Environmental Protection Agency (EPA)
2004-08
U.S. Environmental Protection Agency, Washington, D.C. <a rel="nofollow" class="external text" href="http://www.epa.gov/npdes/pubs/csossoRTC2004_chapter02.pdf">"Report to Congress: Impacts and Control of CSOs and SSOs."</a> Document No. EPA 833-R-04-001