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Watershed Planning and Restoration Program

Water Quality

Total Maximum Daily Load (TMDL)

On a semi-annual basis, the Utah Division of Water Quality (DWQ) develops lists of impaired waters in the state. “Impaired waters” are those waterbodies that currently fail to meet water quality standards established by the State even after point sources have implemented the minimum required levels of pollution control technology.

This semi-annual assessment is mandated under section 303(d) of the Clean Water Act and results in the listing of impaired waters on what is known as the "303(d) list. Subsequent to listing, the State is required to develop a Total Maximum Daily Load (TMDL) to reduce pollutant levels in impaired waters.

TMDL studies in the Jordan River watershed:

Jordan River TMDL
Little Cottonwood Creek TMDL
Emigration Creek TMDL


TMDL Explained

A TMDL is a calculation of the maximum amount of a pollutant that a waterbody can receive on a daily basis and still meet water quality standards. The TMDL process consists of the following steps:

  1. Review existing water quality data
  2. Identify sources and causes of pollutants
  3. Identify water quality goals
  4. Establish the amount of pollutant that can be allowed in total
  5. Allocate allowable pollutant loads
  6. Identify and implement measures to achieve and maintain water quality standards
  7. Monitor to assure that goals are met

The TMDL process results in load allocations to each pollutant contributor. These allocations often result in regulatory controls and mandates.

TMDL pie chart

Visit the Utah Division of Water Quality website for more information about TMDL studies,