National Pollutant Discharge Elimination System (NPDES)

Combined Sewer Overflows Policy, Reports, and Training

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EPA released the following policy memoranda that clarify aspects of the CSO program and addresses implementation issues.

Implementation of the Nine minimum Controls, November 18, 1996 – Calls attention to the January 1, 1997 deadline for implementing minimum controls by NPDES permittees with CSSs.
Implementation of the CSO Policy, May 19, 1998 – Discusses implementing the CSO control policy and where heightened efforts are necessary.
Water Quality-Based and Technology-Based CSO Requirements, July 7, 1999 – Clarifies that permitting authorities must determine best available technology (BAT) and best conventional pollutant control technology (BCT) on a case-by-case basis during the permitting process. It also suggests that permitting and water quality programs coordinate closely to reach agreement on the requirements of a long-term CSO control plan (LTCP).
Financial Capability Assessment (FCA) Framework, November 24, 2014 – Identifies key elements of EPA's approach to evaluating the financial capability of municipalities to inform schedules. The FCA framework provides additional information that could help communities provide a “more accurate and complete picture” of their financial capability.

2016 Report to Congress Combined Sewer Overflows into the Great Lakes Basin - This report assesses the implementation status of long-term CSO control plans (LTCPs) in the Great Lakes Basin. The report also summarizes existing information on the occurrence and volume of discharges from CSOs in the Great Lakes Basin during 2014.
2007 Report to Congress Combined Sewer Overflows to the Lake Michigan Basin – This report assesses the occurrence of CSOs in the Lake Michigan drainage basin. The report identifies EPA actions to ensure that state permitting and enforcement efforts are consistent with the national CSO control policy and Clean Water Act, and lead to further reduction in CSO discharges to Lake Michigan.
2004 Report to Congress – This report presents a comprehensive characterization of CSOs and sanitary sewer overflows (SSOs), including the extent to which they cause environmental and human health impacts, technologies used by municipalities to address their impacts, and resources spent by municipalities to control CSO and SSO discharges.
- Fact Sheet
- 2004 Report to Congress: Impacts and Control of CSOs and SSOs (August 26, 2004)
2002 Report to Congress – This report, delivered to Congress on January 29, 2002, identifies progress made in implementing and enforcing CSO controls prior to, and because of, the 1994 CSO control policy.