Total Maximum Daily Loads Frequently Asked Questions

Find answers to frequently asked questions regarding bacteria in our region’s waterbodies, water quality monitoring, and the plans created to address these issues.

The Houston-Galveston Area Council (H-GAC) is a council of governments representing 13-counties and 126-plus cities in the Houston-Galveston region.

H-GAC manages several Water Resources programs and initiatives in cooperation with local communities and state and federal agencies. Activities range from identifying and resolving water quality issues and providing data and technical assistance, to public outreach activities and volunteer opportunities.

The Texas Commission on Environmental Quality is the environmental agency for the state of Texas. The TCEQ oversees all aspects of planning, permitting, and monitoring to protect the state's water resources.

Bacteria are microscopic, single-celled organisms that are so small, over five million could fit on the head of a pin.


For this project, we are looking at indicator bacteria, E. coli and enterococcus.

E. coli is the indicator bacteria for contact recreation in fresh water. Enterococcus is the indicator bacteria for salt water. Both types are found in the intestines of animals, including humans, and deposited through fecal waste.

They are called indicator bacteria because their presence is an indicator that dangerous pathogens may also be present.

High levels of these bacteria indicate an increased risk of gastrointestinal illness and infections.

Bacteria can enter waterbodies through direct discharge of waste by animals into the water, from agricultural and stormwater runoff, and from untreated or poorly treated human sewage.

Contact recreation is any water-based activity, including wading, swimming, skiing, diving, tubing, surfing or boating, where water might accidentally be ingested.

Contact recreation impairments simply mean that the water quality of a specific waterbody could impact your health, if ingested.

If a waterbody near you has a bacteria impairment, be careful when using the waterbody recreationally. Never swim or wade with open cuts or sores, wait three days after it rains to use the water recreationally, and do not intentionally ingest the water.

Visit H-GAC’s interactive Water Resources Information Map to find out about specific waterbody impairments.

There are several categories for recreational water use, known as the Texas Surface Water Quality Standards.

One such standard is Primary Contact, which includes activities where a significant risk of ingesting the water exists, such as wading by children, swimming, water skiing, diving, tubing, surfing, and whitewater activities.

Visit TCEQ’s website for more information.

Some bacteria impairments are not for contact recreation, but are for oyster consumption. Fecal coliforms are the indicator for that. Some waterbodies in this project area currently have oyster consumption advisories.

Surface water quality is monitored through the Clean Rivers Program (CRP).

H-GAC is the state-designated lead partner agency for the San Jacinto River Basin, the Trinity-San Jacinto Coastal Basin, the San Jacinto-Brazos Coastal Basin and the Brazos-Colorado Coastal Basin. These basins comprise the H-GAC CRP project area, which includes all or a portion of 15 counties, more than 400 sampling sites and seven regional partners.

The TCEQ's Surface Water Quality Monitoring (SWQM) Program then assesses CRP data to provide a basis for effective policies that promote the protection, restoration, and wise use of surface water in Texas. Learn more about SWQM.


H-GAC and local partners make suggestions for additional monitoring locations, working in partnership with TCEQ.

TCEQ divides each waterbody into segments and then into smaller assessment units that share similar hydrological characteristics, to better compare data for reporting purposes. There are typically several monitoring sites for each assessment unit.

For H-GAC CRP monitoring sites, water quality testing takes place quarterly, at a minimum. Monitoring sites that are a part of other water quality studies or projects may be monitored more frequently.

It could, though it is unlikely.

Drinking water is treated prior to human consumption and use, which removes impurities and bacteria. Individuals who drink untreated surface water, however, may become ill.

There are several paths available to address bacteria is area waterbodies, a TMDL being one of them.

A Total Maximum Daily Load (TMDL) is a regulatory process triggered by impairments in a specific stream segment or segments that calculates the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards. TMDLs allocate a portion of that load to the various sources of that pollutant, with sources characterized as either point sources that receive a wasteload allocation, or nonpoint sources that receive a load allocation.

Watershed Protection Plans (WPPs) are locally driven, voluntary projects that serve as a mechanism for addressing complex water quality problems that occur across multiple jurisdictions.

The goal of a WPP is to protect healthy waterbodies from potential pollutant threats and to restore polluted waterbodies.

An I-Plan is a formalized, written plan developed by stakeholders that typically results from a TMDL. I-Plans contain policy recommendations for the community, those with various TCEQ permits, and local governmental entities.

I-Plans usually focus on a single or very narrow set of water quality parameters, such as bacteria.

Your actions can directly impact the quality of area waterbodies.

Picking up after your dog, keeping on-site sewage facilities properly maintained, and properly disposing of fats, oils, grease, as well as toilet wipes, can all go a long way toward improving and protecting local water quality.