Surface Water Quality Assessments

MDEQ monitors the quality of surface water throughout the state. Monitoring data and information are used to make water quality assessments. Assessments are general characterizations of water body health. The state’s most comprehensive assessment report is the Federal Clean Water Act Section 305(b) Water Quality Inventory Report.

About Assessments

Water Quality Assessments are technical reviews of physical/chemical, bacteriological, biological, and/or toxicological data and information to determine the quality of the state’s surface water resources. Monitoring data are compared to the “State of Mississippi Water Quality Criteria for Intrastate, Interstate, and Coastal Waters” in order to make decisions on whether a water body is supporting or not supporting its designated uses such as aquatic life support, water contact recreation, fish/shellfish consumption, and drinking water.

Assessments answer questions like:

  • Is a water body safe for swimming?
  • Can I eat the fish out of this stream/ lake/ estuary?
  • Can fish and other aquatic life live safely and reproduce in this water body?

If a water body is determined to be not supporting one of its uses, then the water body is considered impaired. The causes and sources of the impairment are then determined. These waters are subject to further monitoring and are listed on the state’s Impaired Waters List. The EPA has national guidance on assessing and listing impaired waters. This guidance is known as the Consolidated Assessment and Listing Methodology (CALM). To learn more about CALM, click here to view EPA’s CALM website.

Section 305(b) Assessment Reports

MDEQ reports on the status of the state’s surface and ground waters every two years. This information is sent to EPA and is available to the public. For more information on the Section 305(b) Report, click here to contact the Section 305(b) Program Coordinator. To review recent Section 305(b) Reports, click below.

Related Water Quality Documents