Minnesota Thermal Discharges regulations & environmental compliance analysis

Minnesota Thermal Discharges: What you need to know

Governing Law and Regulations

Minnesota Water Quality Standards: Minnesota Rules (MR) 7050.0180 and MR 7050.0220

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Thermal limitations: MR 7050.0220

Outstanding resource value waters (ORVWs): MR 7050.0180

Indirect discharges: MR 5900.4500

Regulatory Agency

Minnesota Pollution Control Agency (MPCA) Environmental Analysis and Outcomes Division

Metropolitan Waste Control Commission (MWCC)

See ADDRESSES & CONTACTS for addresses and telephone numbers.

See national section for basic information and federal regulations.

Comparison: State vs. Federal

Rules. Minnesota has established specific guidelines for thermal discharges into its waters. The state's regulations generally follow the federal Clean Water Act (CWA). See the national section THERMAL DISCHARGES for more information.

Administration and enforcement. MPCA's Environmental Analysis and Outcomes Division is responsible for the administration and enforcement of the state's rules for developing water quality standards for lakes, rivers, and streams, including standards for thermal discharges.

State Requirements


MR 7050.0220

Thermal discharge limitations for state receiving waters are provided on the individual discharge permits. Generally, however, temperatures may not be increased more than 5°F above the natural temperature in streams, and more than 3°F above the natural temperature in lakes. Under no circumstances may the average daily temperature exceed 86°F. These levels are based on a monthly average of the maximum daily temperatures of the receiving water. See the terms of your discharge permit and contact MPCA for additional guidance.

Thermal Discharge Variances

Dischargers may apply for variances from the thermal discharge ...

Read more about Thermal Discharges