Aquatic Pesticides

The application of pesticides onto Delaware surface water requires a permit from the Department of Natural Resources and Environmental Control (DNREC). Permits for this activity are part of the National Pollutant Discharge Elimination System (NPDES).


In 2009, the U.S. Sixth Circuit Court determined that the application of biological pesticides and chemical pesticides with residuals to waters regulated under the provisions of the federal Clean Water Act (CWA) must be regulated by a NPDES permit.

On September 11, 2012, DNREC adopted the Regulations Governing the Discharges from the Application of Pesticides to Waters of the State as Subsection 9.8 (PDF) of the Regulations Governing the Control of Water Pollution (7 DE Admin. Code 7201).


The regulations cover discharges of biological pesticides and chemical pesticides that leave a residue from the following pesticide use patterns: mosquito and other flying insect pest control, weed and algae control, animal pest control, and forest canopy pest control.


DNREC has issued a NPDES General Permit for the application of Aquatic Pesticides: NPDES Permit Number DE 0051241.


As of March 2020, DNREC offers an electronic reporting system for the Aquatic Pesticide program. The Electronic Notice of Intent (eNOI) system helps those covered by general NPDES permits meet their reporting requirements.

To aid in the transition, DNREC offers a guide to creating accounts and generating submissions.

Those unable to comply with the electronic reporting requirement should contact Lydia Smith, at 302-739-9946 or

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