Total Maximum Daily Loads

NRCS scientist and farmer working with nutrient management software.This page contains introductory information regarding total maximum daily loads (TMDLs). For more specific information, including regional issues and congressional activities, see the menu to the right.

USDA. National Agricultural Library.

Searches for TMDL-related citations in AGRICOLA, NAL's catalog of books and articles. Some full text materials are available.

New Hampshire Department of Environmental Services.

"The term 'total maximum daily load' (TMDL) refers to the calculation of the maximum amount of a pollutant that a waterbody can receive, and attain or maintain water quality standards for its designated use. The TMDL calculation allows for the determination of a carefully identified allowable pollutant load equivalent to the sum of the waste load allocations (WLA) for point sources, load allocations (LA) for nonpoint sources and naturally occurring background sources, and an allocation of that load among the pollutant's sources. The TMDL calculation is required to account for seasonal variations and it must include a margin of safety (MOS) that accounts for uncertainty and any lack of knowledge concerning the relationship between effluent limitations and water quality."