Delaware Thermal Discharges regulations & environmental compliance analysis

Delaware Thermal Discharges: What you need to know

Governing Law and Regulations

Water pollution control: 7 Delaware Administrative Code (DE Admin Code) 7201

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Surface water quality standards: 7 DE Admin Code 7401

Thermal standards: 7 DE Admin Code 7401.4.5.1

Freshwater: 7 DE Admin Code 7401.

Cold water fisheries: 7 DE Admin Code 7401.

Marine waters: 7 DE Admin Code 7401.

Mixing zones: 7 DE Admin Code 7401.6.4.2

Variances: 7 DE Admin Code 7201.6.22

Regulatory Agencies

Delaware Department of Natural Resources and Environmental Control (DNREC) Division of Water Resources (DWR)

U.S. Environmental Protection Agency (EPA) Region 3

See ADDRESSES & CONTACTS for addresses and telephone numbers.

See national section for basic information and federal regulations.

Comparison: State vs. Federal

Rules. The state has adopted federal requirements for addressing thermal discharges using the federal Clean Water Act (CWA). In addition, Delaware regulates water temperature under its water quality standards for certain surface waters and streams.

Administration and enforcement. DNREC's DWR administers and enforces the state's surface water quality standards, including for temperature criteria.

State Requirements


The temperature of wastewater discharges is monitored under the National Pollutant Discharge Elimination System (NPDES) permit program. See the state section NPDES PERMIT for more information. The state's NPDES program requires permits for any wastewater discharges from a point source into state waters. All NPDES permits require compliance with state water quality standards, including temperature criteria as described in the following sections, and are dependent on the receiving water body.


7 DE Admin Code 7401.4.5.1

Delaware has established state-specific thermal standards to protect designated uses in state surface waters. DNREC may mandate additional limitations on a site-specific or seasonal basis in order to provide incremental protection for early life stages of fish.

Read more about Thermal Discharges