Surface water quality levels in some Texas lakes, rivers is poor, officials say

BANDERA, Texas – Signs posted on Bandera Park at the Medina River tell people not to swim in the water, warning of elevated bacteria levels.

David Mauk, general manager of the Bandera County River Authority and Groundwater District, said the high heat and lack of rain are helping bacteria thrive in some rivers and lakes.

“These are the headwaters, and generally, they are pretty pristine waters. But when it’s not flowing, and you get temps over 90 degrees and over 100, you are going to see things introduced,” he said.

Surface water testing is done every two weeks in different locations of the headwaters of the San Antonio and Medina basins, the Nueces and Sabina rivers and Medina Lake.

“People are very tied to the river system here, and when the river system suffers like this, people, animals, the fish, they’re going to suffer,” Mauk said.

Surface water testing data is public. The key number to look for when checking water conditions is the number followed by the acronym MPN, which stands for Most Probable Number. See the data here.

In Bandera, the test levels are coming back high for E. Coli. The number, usually between 50 to 100 MPN, is well over 700 in the last test completed.

Where’s the water? Texas swimming spots drying up due to extreme heat, lack of rain.