Skip to content

What is the 303 (d) List of Impaired Waterbodies?

The Clean Water Act (CWA) was passed in 1972 to protect the country’s waterways. Section 303(d) of the Act requires each state to list surface waters that do not meet water quality standards. These waters are known as impaired waterbodies. The purpose of the 303(d) list is to know which waterbodies are impaired so that efforts can be made to improve them. The 303(d) list is put together with information from South Carolina’s Surface Water Quality Monitoring Program. The South Carolina Department of Health and Environmental Control (DHEC) has an in-depth program for monitoring the quality of waterbodies in South Carolina. Over 2,000 specific water sites are tested to provide a picture of water quality in the State. Information from the testing sites is used to prepare the 303d list.

There are three ways for a site to be removed from the 303(d) list.

  1. The waterbody must once again begin to meet water quality standards.
  2. A Total Maximum Daily Load (TMDL) is developed for the waterbody.
  3. The waterbody was placed on the list in error and is removed.

A TMDL shows how much of a pollutant from direct sources and from diffuse sources (wet weather runoff pollution) that a waterbody can receive and still have acceptable water quality. However, having a TMDL does not mean that the site is meeting water quality standards. Water improvement is expected to happen after a TMDL has been implemented. So far, 320 TMDLs have been approved in South Carolina. TMDLs are being implemented through permitting program activities and through awarding nonpoint source (runoff) pollution reduction grants. Grant winners work to decrease or remove pollutants reaching a waterway. A total of 22 grant projects implementing 69 fecal coliform TMDLs have been awarded, and 11 million dollars has been spent on TMDL implementation. Water quality monitoring, the 303d list, and TMDLs are all part of a system that allows DHEC to monitor for waterbodies that need attention and work toward their restoration and continued protection.

Back to Swimming Advisory Main Page