2019 Water Maintenance

Town of Little Elm News Release for NTMWD Water Maintenance

Each spring for about one month, the North Texas Municipal Water District suspends its use of ammonia to allow the remaining chlorine to keep the water disinfected as it travels through the system. This temporary change in disinfectant helps maintain the system and high water quality year round. The primary reason the NTMWD performs this action is to help reduce the potential for bacterial growth in pipes. This year's maintenance will be performed from March 4 to April 1. 

What Does This Mean for Little Elm residents? 

As Little Elm gets its water from the NTMWD, you may notice a more distinct chlorine smell to your tap water, however, water remains safe for use and consumption.

Even at very low concentrations, some people may be more sensitive to taste, smell, and skin contact with chlorine. Here are some simple steps to help minimize those effects:

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Download the NTMWD Spring 2019 Maintenance information here

Common FAQs

What is NTMWD’s routine water treatment process?

Disinfection of water is typically a two-step process. The first step is to inactivate or kill microorganisms, such as bacteria, parasites and viruses, during treatment. The second step makes sure water remains disinfected and safe for drinking as it travels long distances through pipes all the way to the tap. Most of the year, NTMWD disinfects its water using a combination of ozone and chlorine (first step) and then chloramine, which is the combination of ammonia and chlorine (second step).

Why do you use chlorine/chloramine to disinfect water?

Chlorine is the most widely used water disinfectant in the world. Only chlorine-based disinfectants (including chloramine) are approved by the U.S. Environmental Protection Agency (EPA) for the second step of water disinfection. According to the Texas Commission on Environmental Quality (TCEQ): “Treatment prior to distribution may utilize a number of different disinfectants, but a public water system is required to use either chlorine or chloramine in the distribution system.”

EPA requires water treatment facilities to maintain a minimum chlorine level of 0.5 milligrams per liter (mg/l)—or parts per million (ppm)—during normal operations and a maximum running average 0.5 of 4 mg/l (or 4 ppm). These levels are safe for use or consumption.

Why is the temporary change in disinfectant necessary?

Each spring for about one month, NTMWD temporarily changes the disinfectant used in the second step of water treatment. This is necessary to help maintain the system and high water quality year-round. During this time, ammonia is temporarily suspended and only chlorine is used to maintain water disinfection from the time it leaves the treatment plant as it travels long distances to the tap. Chlorine levels in the water are consistent with year-round operations. However, the discontinuation of ammonia can make the presence of chlorine more noticeable. Cities may help with this process by flushing water out of fire hydrants during this time, which helps move the chlorine through the system faster. The EPA estimates up to 40 percent of water providers who use chloramine conduct this process.

Does NTMWD add more chlorine during this period?

No, test results verified by the TCEQ show chlorine levels during the temporary change in disinfectant process are consistent with normal year-round operations.

Why did I notice a stronger presence of chlorine last year?

NTMWD acknowledges that there was more public concern expressed in 2018 about the water quality during the temporary change in disinfectant. NTMWD took these concerns seriously and retained outside water quality experts to evaluate if there was anything different that would have impacted water quality during the 2018 one-month change.

Here’s what NTMWD found:

  • Untreated and treated water quality was not significantly different during the 2018 change period from other years.
  • The levels of chlorine in the water being piped from our main treatment plant in Wylie were consistent with previous years.
  • Slightly higher chlorine levels at some city delivery points were noted in 2018 compared to previous years, but these were minor in nature and do not appear to be the main reason for public concern.
  • Lower water demand during the 2018 temporary change in disinfectant due to significant rainfall may have led to more odor since water was staying in the pipes longer.

Get more answers here




Why do you use chlorine/chloramine to disinfect water?

Chlorine is the most widely used water disinfectant in the world. Only chlorine-based disinfectants (including chloramine) are approved by the U.S. Environmental Protection Agency (EPA) for the second step of water disinfection. According to the Texas Commission on Environmental Quality (TCEQ): “Treatment prior to distribution may utilize a number of different disinfectants, but a public water system is required to use either chlorine or chloramine in the distribution system.”


EPA requires water treatment facilities to maintain a minimum chlorine level of 0.5 milligrams per liter (mg/l)—or parts per million (ppm)—during normal operations and a maximum running average 0.5 of 4 mg/l (or 4 ppm). These levels are safe for use or consumption.