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Columbia, South Carolina Clean Water Act Settlement

(Atlanta, GA - September 10, 2013) - The Department of Justice, U.S. Environmental Protection Agency (EPA), and South Carolina Department of Health and Environmental Control (DHEC) announced a proposed settlement today with the City of Columbia to resolve violations of the Clean Water Act (CWA), including unauthorized overflows of untreated raw sewage. Columbia has agreed to undertake a thorough assessment of, and implement extensive improvements to, its sanitary sewer system at an estimated cost of $750 million. 

Overview of Sewer Authority

The City of Columbia, South Carolina owns and operates a separate sanitary sewer system. The City’s system includes the Columbia Metro wastewater treatment plant and the wastewater collection and transmission system.

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Columbia violated Section 301 of the Clean Water Act and terms and conditions of its National Pollutant Discharge Elimination System (NPDES) permit. Columbia’s alleged violations include sanitary sewer overflows (SSOs) and effluent limit exceedances.

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Injunctive Relief

Under the consent decree, Columbia must assess and rehabilitate its sewer system within 12 years. Columbia will do this work in a phased, prioritized manner. The goal is to eliminate SSOs and develop and implement specific management, operation and maintenance programs to address deficiencies in Columbia’s sewer system. When the injunctive relief is implemented, the settlement will help reduce direct exposure of raw sewage to populations in Columbia.

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Pollutant Reductions

EPA estimates the injunctive relief provided for in the Consent Decree will result in the annual reduction of pollutant loadings as follows:

  • Total suspended solids – 1,178 pounds
  • Biological oxygen demand – 1,127 pounds
  • Total nitrogen – 183 pounds
  • Total phosphorus – 26 pounds

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Health and Environmental Effects

  • Total Suspended Solids (TSS) – TSS indicates the measure of suspended solids in wastewater, effluent or water bodies. High levels of TSS in a water body can diminish the amount of light that penetrates the water column and reduce photosynthesis and the production of oxygen. 
  • Biological Oxygen Demand (BOD) – BOD is an indirect measure of the biologically degradable material present in organic wastes. High BOD means there is an abundance of biologically degradable material that will consume oxygen from the water during the degradation process. It may take away oxygen that is needed for aquatic organisms to survive. 
  • Nutrients - Excess levels of nitrogen and phosphorus in waters can produce harmful algal blooms. These blooms contribute to the creation of hypoxia or “dead zones” in water bodies where dissolved oxygen levels are so low that most aquatic life cannot survive.

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Civil Penalty

Columbia will pay a total of $476,400 as a civil penalty for its Clean Water Act violations to the United States and the State of South Carolina. Columbia also agreed to spend $1,000,000 on a supplemental environmental project in environmental justice areas of concern in the City. The penalty in this case was derived according to the Clean Water Act Settlement Penalty Policy.     

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State Partner

The State of South Carolina is a co-plaintiff.

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Comment Period

Once the proposed consent decree is lodged with the Court, the settlement will be subject to a 30-day public comment period. 

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For more information, contact:

Carol DeMarco
Water Enforcement Division
1200 Pennsylvania Ave., NW (Mail Code 2243A)
Washington, DC  20460
(202) 564-2412
Carol DeMarco (

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