Michigan Thermal Discharges regulations & environmental compliance analysis

Michigan Thermal Discharges: What you need to know

Governing Law and Regulations

National Pollutant Discharge Elimination System (NPDES) permit requirements: 40 CFR 122

For a Limited Time receive a FREE EHS Report "Recordkeeping for EHS Managers." This special report contains a recordkeeping checklist to help you keep track of your records for major environmental laws and OSHA's Hazard Communication Standard. Download Now

General conditions: Michigan Administrative Code (MAC) r. 323.1069

Thermal standards:

Great Lakes: MAC r. 323.1070

Inland lakes: MAC r. 323.1072 and MAC r. 323.1073

Rivers, streams, and impoundments: MAC r. 323.1075

Regulatory Agencies

Michigan Department of Natural Resources and Environment (DNRE) Water Resource Division

U.S. Environmental Protection Agency (EPA) Region 5

See ADDRESSES & CONTACTS for addresses and telephone numbers.

See national section for basic information and federal regulations.

Comparison: State vs. Federal

Rules. Michigan has established specific effluent guidelines for temperature as part of the NPDES permitting system. Wastewaters discharged in Michigan must meet specific temperature requirements which are specific to water bodies and regions of the state.

Administration and enforcement. DNRE's Water Resource Division is responsible for the administration and enforcement of the state's thermal discharge regulations.

State Requirements


MAC r. 323.1069

In all waters of the state, temperature measurement is usually taken within 1 meter of the surface, unless measurement at a deeper depth is required. While monthly maximum temperatures may be excluded for short periods, these increases can never be more than the natural water temperature plus the increase allowed at the edge of the mixing zone. Generally, all efforts have to be made to maintain the natural daily and seasonal temperature fluctuations of the receiving waters. The waters of the state have been separated by type and location, with thermal standards set for specific regions and water bodies.


Read more about Thermal Discharges