There was a slight decrease in water quality in Bexar County 2022 and 2023.
The San Antonio River Authority (SARA) monitors and reports on water quality data throughout its four county jurisdiction. The main goals of tracking and reporting water quality are: (1) to help communities protect water quality by identifying ways to reduce the amount of stormwater flows in a community, and (2) to educate stakeholders on the wide range of policies and regulations that have water quality implications.
As the City of San Antonio and surrounding Bexar County community continue to develop, land that is currently vegetation will be converted into paved surfaces. As more natural surfaces are paved and developed, less water absorbs into the ground and instead flows over impervious surfaces and into storm drains, picking up pollutants and carrying them to creeks and rivers. The untreated rainwater that goes into storm drains and directly to our creeks and rivers is known as stormwater runoff. The pollutants picked up by stormwater include, but are not limited to, oil, fertilizers, bacteria (including E. coli), heavy metals, gasoline, and sediment.
Stormwater runoff (or non-point source pollution) is the most significant contributor to water quality degradation in the San Antonio River Watershed. It is also the most difficult to control and mitigate, which means recognizing efforts through Low Impact Development/Green Stormwater Infrastructure Best Management Practices.
E. coli bacteria levels in surface waters are highly dependent on stormwater runoff. When there is a wet year, E. coli levels tend to be high, and when there is a dry year, E. coli levels are lower. In 2023, more than 40% of Texas, including Bexar County, was in an extreme drought, which coincided with one of the hottest years of record.
