A TMDL or Total Maximum Daily Load is a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards. Water quality standards identify the uses for each waterbody, for example, drinking water supply, contact recreation (swimming), and aquatic life support (fishing), and the scientific criteria to support that use. The Clean Water Act, section 303, establishes the water quality standards and TMDL programs.

Glossary of stream, lake and watershed terms. (n.d.). Retrieved February 08, 2017, from http://kingcounty.gov/services/environment/watersheds/general-information/glossary.aspx