MSD's Consent Decrees

Water Through Trees

Every year, about 11.5 billion gallons of raw sewage - mixed with stormwater - overflows from MSD's combined sewer system into local streams and rivers and also backs up into homes and businesses. Additionally, about 100 million gallons overflow annually from sanitary sewers.

To address this issue and achieve compliance with the Clean Water Act, the City of Cincinnati and Hamilton County entered into two federal Consent Decrees and developed a $3.1 billion Wet Weather Improvement Plan (WWIP):

  • Interim Partial Consent Decree on SSOs, 2002
  • Global Consent Decree on CSOs and Treatment Plants, 2004
  • Wet Weather Improvement Plan (WWIP), 2010
  • Project Groundwork

    Project Groundwork (click for Project Groundwork website)The Wet Weather Improvement Plan was rebranded as Project Groundwork in 2009, with a separate website and logo. Project Groundwork is being conducted in two phases: Phase 1 (2009-2018) and Phase 2 (after 2018). Phase 1 is currently underway, with 97 of the 114 projects completed. Phase 1 includes the Lower Mill Creek Partial Remedy, which is designed to reduce overflows into the Mill Creek by 1.78 billion gallons a year, primarily through the Lick Run Project. Phase 2 is currently under development.


    In the late 1980s and 1990s, the federal government, through the Clean Water Act, called for the elimination of sanitary sewer overflows (SSOs) and a reduction of discharges from combined sewer overflows (CSOs). This action affected every wastewater system in the country, including MSD. Increased scrutiny from the U.S. Department of Justice (DOJ) and U.S. Environmental Protection Agency (EPA) brought the issue to the forefront in the late 1990s as these government bodies began enforcing the ruling in large cities and leveling heavy civil penalties on those out of compliance.

    In 1999, MSD, which had already begun eliminating SSOs and reducing CSOs, entered into negotiations with the EPA, DOJ, and the State of Ohio to establish a formal remediation program that would be recognized and supported by the government, but also was affordable for local ratepayers. These negotiations resulted in the two Consent Decrees and the Wet Weather Improvement Plan (WWIP).