By John Dobberstein, Editor
COWETA — The city of Coweta disclosed in a notice sent to residents Friday that sampling for some contaminants in drinking water didn’t occur for several years due to staff turnover at the Public Works Authority.
The city said no sampling occurred for radionuclides — radioactive forms of elements — for 6 years beginning in 2020, and no sodium testing was done for volatile organic compounds, lead or copper from 2023 through 2025. The city also didn’t test for sodium for all of 2025.
According to the city, the Coweta PWA, “experienced several changes in management” in the Public Works department during the period. “Due to a misunderstanding, the current staff were not aware that the water consultant did not take samples for the above contaminants, and that lead and copper samples were not submitted by the previous Public Works director.”
Samples have recently been taken and reported to the Oklahoma Department of Environmental Quality (ODEQ) and will be taken per the required schedule moving forward, the city said.
None of the violations, according to the city, are considered emergencies and there is no reason to suspect potential adverse health effects. But due to the lack of testing the city said it, “cannot be sure of the quality of your drinking water during that time.”
The city also said its water exceeded the standards for haloacetic acids (HAA5). The standard of maximum contaminant level (MCL) for HAA5 is 0.60 mg/L, which is determined by averaging all the samples collected at each sampling location for 12 months. Levels for the first quarter of 2006 were 0.061 mg/L, barely above the standard level.
The potential reason for the violation was due to an automatic flusher at one of its facilities being taken offline due to freezing temperatures, the notice said. “In addition, numerous complaints were received that the flushing was causing saturation issues on a neighboring property,” the city’s notice said.
To strengthen the system the city’s Public Works Department will be adding 200 feet of 6-inch C900 water pipe to extend the city’s water main, and a 6-inch fire hydrant with an automatic flusher will be installed, allowing water to always remain fresh and avoiding the production of HAA5.
The city said no action is needed by customers, although people with a severely compromised immune system, or who have an infant or are elderly may be at increased risk and should seek advice about drinking water from their health care providers.
The city acknowledged some people who drink water containing HAA5 in excess of the MCL over many years may experience problems with their liver, kidneys or central nervous system, and may have an increased risk of getting cancer.
Coweta’s drinking water system has seen many challenges in recent years due to insufficient routine maintenance and the failure to address factors contributing to high levels of Disinfection Byproducts (DBPs) in Coweta’s water distribution system, City Manager Julie Casteen has said.
DBPs form when disinfectants — specifically chlorine in our case — react with naturally occurring organic matter in the water during the disinfection process. This reaction can generate compounds such as trihalomethanes (TTHMs) and haloacetic acids.
The city entered into a Consent Order with the ODEQ in 2024 after the receiving multiple notices of violation for TTHMs, HAA5 and chlorine residual levels. The DEQ required several major infrastructure and operational improvements to address chlorine treatment, system turnover and reduction of disinfection byproduct precursors.
This included modifications to the Skyview water storage tank which have been completed, and expected reservoir sludge removal to reduce organic material entering the treatment process.
The order requires the city to attain compliance with water treatment standards by Oct. 1, 2027.
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