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Total Maximum Daily Load Program: Communities Working Together to Improve Water Quality

A program that brings communities together to take care of Texas by improving the quality of their streams, lakes, and bays.
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The Total Maximum Daily Load (TMDL) program brings communities together to take care of our streams, lakes, and bays. Working with stakeholders in watersheds where pollution is limiting the full beneficial use of surface waters, the TMDL program develops targets for reducing pollution and helps communities build plans to improve their waterways.

A TMDL is a scientifically-derived target that tells us the greatest amount of a particular substance that we can add to a waterway and still keep it healthy. These substances are not necessarily harmful in and of themselves. For example, phosporus 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 in a creek, lake, or bay—activities called “contact recreation” in the state’s standards for water quality.

The TMDL gives us an measurable way to target our efforts to protect and improve the quality of our streams, lakes, and bays.


About TMDLs, I-Plans, and water quality


Stakeholder Meetings

Projects of the TMDL Program

Protecting people and aquatic species by reducing pollution in impaired or threatened waterways.

TMDLs and Their Implementation

What TMDLs are and how TCEQ and stakeholders make a difference in the quality of our waterways

Participating in TMDL Projects

How to get involved in your watershed

Receive notices about TMDLs and I-Plans being developed, training, grant opportunities, and requests for proposals

Developing TMDL Projects

Guidelines for organizations that develop or implement TMDLs for Texas waterways

All Impaired Waters Adobe Acrobat PDF Document

Categories 4 and 5 of the Texas Integrated Report of Surface Water Quality

Segments with TMDLs

The TCEQ must consider TMDLs that have been adopted by the commission and approved by the EPA in permits it issues under the Texas Pollutant Discharge Elimination System (TPDES).

Preserving and Improving Water Quality

An overview of how the TCEQ defines, measures, evaluates, and manages the quality of surface waters in Texas

The Atlas of Texas Surface Waters and GIS data for classified segments and other hydrology layers

For More Information

Call 512-239-6682, or send us an e-mail at

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