2019 Temporary Change in Disinfectant (Chlorine Maintenance)

The 2019 Temporary Change in Disinfectant (TCD) is set to run 28 days from March 4th to April 1st, 2019.  Allen’s water provider, the North Texas Municipal Water District (NTMWD) has performed this water system maintenance since 2007.  The Texas Commission on Environmental Quality (TCEQ) approves this process for water system maintenance. 

Water producers must add disinfectants to their treated water to assure that unhealthy microorganism cannot grow in water distribution systems. Chloramine, a mixture of chlorine and ammonia, or just chlorine, are typically used for disinfection. Chloramine is not as capable of destroying microorganism as chlorine but it lasts longer and carries less taste and odor than chlorine.  However, many water systems switch to chlorine-only disinfection for 28 days a year to take advantage of chlorine’s increased effectiveness to kill microorganisms. The TCD process is considered as “spring cleaning” for the water system in anticipation of the warmer summer months when microbial growth may be increased. Whether, chloramine or chlorine is in use, the concentration of either disinfectant in the water produced is the same and is kept under the Environmental Protection Agency’s concentration limit. However, customers may think the concentration is actually higher and have safety concerns as chlorine-only disinfection results in a stronger taste and odor. 

During the 28-day TCD in 2018 that ended March 26, 2018, several residents expressed concerns about the taste, smell and safety of our tap water.  

NTMWD collects and processes hundreds of samples each day to ensure the safety of its water. In response to customer concerns, additional water samples were collected from the NTMWD distribution system on March 16, 2018 and tested by an independent lab. These samples were found to be well within the bounds of regulatory standards for disinfectant concentration. Details of that lab report are available on the NTWMD website.

In addition, a TCEQ water quality inspector visited Allen on March 22, 2018. She sampled five locations within our city and found both the free chlorine and total chlorine levels were well below mandated limits. The City of Allen also sent water quality crews to homes at the request of residents and water samples from these homes also showed chlorine levels below the limit set by the EPA.

On March 30, 2018, NTMWD released a comparative report that shows the chlorine residual levels prior to the chlorine maintenance period and chlorine residual levels during the chlorine maintenance test period for both 2017 and 2018 at twelve TCEQ approved sample sites. These samples were analyzed for EPA compliance and sent to TCEQ. These tests show that the annual average chlorine disinfection residual levels comply with mandated regulations and that levels were similar prior to and during the annual TCD period.

Annual TCD is an approved and heavily-regulated process performed to make water safer based on our specific water supply (lake surface water) and distribution system. It helps eliminate dangerous and potentially deadly bacteria which could proliferate in pipes during summer months – including those that cause diseases such as typhoid and cholera. According to NTMWD, 45% of the country performs this same water treatment process.

In response to citizen inquiries, the City of Allen hosted a Town Hall Meeting on April 18, 2018 to directly answer questions from residents. City leaders shared that water is the most regulated service the City of Allen provides to its citizens and explained how Allen works with NTMWD, TCEQ, and the U.S. Environmental Protection Agency (EPA) to ensure our community’s drinking water meets all state and federal standards. Higher standards than those set by the Clean Water and Safe Drinking Water acts and the regulatory agencies that safeguard public health do not currently exist. However, Allen is committed to following all current and future regulations put in place by TCEQ and the EPA as a result of technological advances or updated scientific studies. The City of Allen encourages residents to get involved in water safety by utilizing resources offered by the EPA and TCEQ. Based on citizen suggestions, Allen will enhance its notification efforts ahead of future TCD. Utility customers will receive a direct mail flyer at their residences before the annual TCD period, beginning in 2019.

As a result of rigorous testing and commitment to water quality, Allen has been named a "Superior Water System" by TCEQ, the highest ranking possible. The city publishes an annual Water Quality Report, mailed to every Allen water customer in the spring. The 2018 Water Quality Report will be available in May of 2019. To encourage further transparency, Allen shares historical water quality data on its website, CityofAllen.org/SafeWater and created a Q&A web page to deal with frequently-asked questions about its water testing and treatment process.

NTMWD has provided information about the annual TCD on its website, in an FAQ fact sheet, and in a detailed presentation at the Frisco City Council meeting on April 3, 2018. For citizens with lingering questions, we recommend visiting safewaternorthtexas.com. It offers in-depth information about water treatment processes—including TCD—in a single, easy-to-navigate site. A panel discussion with experts on water quality and treatment processes may also help residents enhance their knowledge about water safety.  NTMWD has also produced a question and answer video with Dr. Scott Phillips, a Medical Toxicologist on the subject of TCD.