The Total Maximum Daily Load or TMDL is a calculation of the maximum amount of a pollutant allowed to enter a waterbody so that the waterbody will meet and continue to meet water quality standards for that particular pollutant. These substances are not necessarily harmful in and of themselves. For example, phosphorus is an essential nutrient, but too much phosphorus can lead to an overgrowth of algae, which in turn can make the water taste bad and reduce the amount of oxygen available to fish and other creatures that live in the water. Another example is bacteria, which occur naturally in both human and animal waste. But too much bacteria can make it more hazardous to swim or wade in a creek, lake, or river—activities called “contact recreation” in the state’s standards for water quality.

A TMDL determines a pollutant reduction target in our waterbodies and allocates load reductions necessary to the source(s) of the pollutant. The TMDL gives us a measurable way to target our efforts to protect and improve the quality of our creeks, lakes, and rivers. Typically, one TMDL is developed for each pollutant that is threatening a waterbody, as such a waterbody may have more than one TMDL in place at a time.

Watch our TMDL video to find out more!

The City of Arlington is committed to reducing pollutant loadings and improving water quality in our watersheds. Arlington is meeting state and federal TMDL requirements by engaging in the following activities:

  • Regional Water Quality pollutant load reduction efforts with other North Texas Cities
  • Bacteria Monitoring in the City’s ten (10) watersheds.
  • Partnering with University of Texas – Arlington on water quality related projects.
  • Identifying areas of necessary and focused efforts to address water quality pollutants of concern, creating measurable goals, and implementing best management practices to reduce pollutant impairments.

For more information on statewide TMDL programs, you may visit the Texas Commission on Environmental Quality (TCEQ) TMDL page:
For more information on what’s happening in the North Texas Region, you may visit the North Central Texas Council of Government (NCTCOG) TMDL page: