(March 26, 2018) The North Texas Municipal Water District’s ‘chlorine maintenance period’ ends today, Monday, March 26. As a result, it may take about a week for Frisco’s water to smell less like chlorine.
Mayor Jeff Cheney and City Manager George Purefoy have released a letter to the Frisco community, responding to questions and concerns about water quality and safety. The attached information comes from Frisco Public Works Assistant Director Kevin Grant.
Frisco’s Drinking Water
The City of Frisco receives drinking water from North Texas Municipal Water District (NTMWD) and then distributes that water throughout our city. The U.S. Environmental Protection Agency (EPA) requires public water systems be tested for as many as 97 federally regulated primary constituents. All drinking water, including bottled water, may contain trace elements. The presence of such trace elements does not necessarily indicate the water poses a health risk.
Frisco’s Water Quality
The City of Frisco follows a detailed water quality testing regimen which includes daily testing (though types of tests vary). The City of Frisco publishes an annual Consumer Confidence Report (CCR) which summarizes the city’s water distribution system and test results during the prior year. Recent testing is reviewed by the city’s operations team and results comply with prescribed state and federal limits. See the 2017 Water Quality Report here.
Why does my water smell like chlorine?
In short, the lack of ammonia during a ‘chlorine maintenance period’ makes your water smell like chlorine.
Since February 26, 2018, the NTMWD has been conducting its annual chlorine maintenance on water transmission and member city distribution systems, which includes Frisco. Today, March 26, the 28-day period ends. The annual chlorine maintenance period helps reduce the need to flush water systems to maintain chloramine residual required by TCEQ. Chlorine maintenance also prevents potential bacteria during warm weather months and helps conserve water.
Because the ‘chlorine maintenance period’ ends today, it may take a week before the chlorine smell is less noticeable. It’s important to note, state and federal regulations require all water systems have a minimum amount of residual disinfectant.
Our water system uses chloramines as a residual disinfectant. Chloramines are a mixture of ammonia and chlorine. The mixture is used because it lasts longer than pure chlorine. Over time, chloramines produce a small amount of free nitrogen (and/or ammonia) which feeds bacteria. If bacteria grows and overpopulates, it may cause problems for the water system because chlorine levels are too low to fight potential diseases.
As a preventive measure, every year the NTMWD removes the potential food source (bacteria) by turning off the ammonia and using pure chlorine as the disinfectant. The NTMWD reports NO additional chlorine is added. The procedure is performed in cooler months because chlorine lasts longer in cooler temperatures. Without nitrogen as a food source, existing bacteria starves and dies, helping prevent more bacteria from growing (blooming) during summer.
Frisco tests its water daily
Frisco’s water division staff conducts 60 to 100 chlorine residual tests a week to ensure our disinfection levels meet state requirements.
So far during March, we have completed 196 chlorine residual tests with the following results:
- Average 2.12 mg/L
- Minimum 0.54 mg/L
- Maximum 3.40 mg/L
According to the TCEQ, the acceptable range for chloramine levels is minimum .5 (milligrams per liter) to maximum 4.0 mg/L. For chlorine, the acceptable levels range from minimum .2 mg/L to maximum 4.0 mg/L. (mg/L is the equivalent of parts per million ppm)
The TCEQ hires an independent laboratory to conduct quarterly water system tests for nitrates, nitrites and Tri-Halomethane (THM). The City of Frisco takes additional measures, testing eight more locations for nitrates and nitrites.
City of Frisco test results for nitrates, nitrites or THM have never reached ‘action level’. In other words Frisco has never exceeded the maximum contaminate level (MCL) established by EPA and considered potentially dangerous to public health.