MSD's Consent Decree

Water Through Trees

MSD is under a federal mandate, known as a Consent Decree, to reduce sewer overflows into local streams and rivers. with the Since 2009, MSD has invested more than $1 billion toward complying with a federal Consent Decree (mandate) to reduce sewer overflows into local streams and rivers. This is about a third of the work necessary to achieve full compliance. This initative is anticipated to take decades to complete.

MSD has reduced combined sewer overflow (CSO) volume by 6 billion gallonssanitary sewers.

Overview of Consent Decree

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).

    MSD is working to complete Phase 1. About 84% of the projects have been completed, or 112 of 133 total projects. 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. Click here for Phase 1 accomplishments to date.

    Phase 2 of Project Groundwork, which is expected to start in 2020, will be implemented in phases over multiple years, starting with Phase 2A. MSD submitted a proposed Phase 2A schedule to the U.S. EPA on June 28, 2018 on behalf of the City of Cincinnati.


    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).

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