July 4 Flooding Caused 1.6 Million-Gallon Sewage Spill Into Concho River

SAN ANGELO, TX — The July 4 storm that dropped a record-breaking 15 inches of rain on San Angelo caused a 1.6 million-gallon sewage spill into the Concho River, city officials confirmed.

The Texas Commission on Environmental Quality (TCEQ) confirmed that the San Angelo incident was the only major wastewater spill reported from the July 4 flooding.

“Risk from this discharge was greatly minimized due to the floodwater dilution and extremely high river flow,” said City of San Angelo spokesperson Lorelei Day in a statement to KXAN in Austin.

Officials said approximately 85,000 acre-feet of storm water poured into O.H. Ivie Reservoir — where both the Concho and Colorado Rivers flow — compared to the five acre-feet of sewage from the spill, which represents about .006% of the storm water in the lake. 

Scott McWilliams, general manager of the Upper Colorado River Authority (UCRA), said the contamination level is too small to detect through standard water testing.

McWilliams said UCRA conducts quarterly testing for bacteria and chemicals as part of the state’s Clean Rivers Program.

The Lower Colorado River Authority (LCRA), which monitors water quality downstream from San Angelo, said bacteria levels typically increase after flooding and may remain elevated for weeks. However, LCRA does not immediately test floodwaters due to rapidly changing conditions, spokesperson Clara Tuma said.

Retail water utilities are responsible for testing and treating drinking water to ensure safety, officials said. The TCEQ also does not routinely sample floodwaters, stating such waters are presumed to be contaminated with bacteria, nutrients, oil, and other hazards after a flood.