(April 3, 2018) The City of Frisco says extra water quality tests, conducted by an independent laboratory, show the city’s water is safe. An additional eight tests for disinfection by-products, specifically total trihalomethanes (TTHM), were performed by Lower Colorado River Authority (LCRA).
The additional TTHM tests, performed at eight locations throughout Frisco, show levels averaging 80.1 parts per billion (ppb). The Texas Commission on Environmental Quality (TCEQ) reports the maximum contaminate level is an average 80 ppb over the course of a year.
“Any single water sample test result (or set of results) may register higher,” said Kevin Grant, Assistant Director of Public Works.
“However, as long as the yearly average is at or below 80 (ppb), the water quality is considered safe and no action is required.”
In the case of Frisco’s recent, eight additional tests, the average level of TTHM is a tenth higher than the state threshold; however, Frisco also reports TTHM tests averaged 44.8 (ppb) over the last three quarters. TCEQ conducts those tests quarterly.
“That means Frisco’s average levels for disinfection by-products, namely TTHMs, are well within the state’s acceptable range.”
Frisco’s ‘extra’ tests for TTHMs were conducted following residents’ concerns the city’s water smelled like chlorine. Frisco contracted with an independent lab to take water samples on March 26 -- the last day of the ‘chlorine maintenance period’ conducted by the North Texas Municipal Water District (NTMWD).
As a result, Grant says Frisco was still receiving water with ‘pure chlorine’ when the water samples were taken and could account for the independent results being a tad higher. Grant says even though the NTMWD ‘turned on’ ammonia after March 26, it can take a couple days for ammonia to mix with chlorine to produce chloramines, a residual disinfectant used to fight disease.
The Texas Commission on Environmental Quality (TCEQ) completes quarterly tests for TTHMs. For more information about Frisco's daily water testing, click here.