Annual System Maintenance: March 4 – April 1, 2024

Water disinfection is required to protect public health and keep our water safe. North Texas Municipal Water District (NTMWD) uses proven and highly effective disinfection methods to treat the water we deliver to over 2 million North Texans. Our annual temporary change in disinfection is required to protect public health. This maintenance procedure is essential to keeping our water safe as it travels to your tap across our 2,200-square-mile service area.

Need for Disinfection

Disinfection is a critical part of water treatment to keep water safe. During NTMWD’s normal water treatment processes, disinfection is a two-step process that first treats the water at the plant and second adds disinfectant to maintain water quality as it travels long distances through pipes to homes and businesses. Both steps are needed to keep tap water free of harmful microorganisms, such as parasites and viruses.

NTMWD uses a combination of ozone and free chlorine (first step) to disinfect water at the treatment plant and then adds ammonia to form chloramines (second step) before leaving the plant. This maintains required water disinfection levels from the time it leaves the treatment plant all the way to your tap. 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.”

Temporary Change in Disinfection
(also known as Annual Chlorine Maintenance)

Each spring for about one month, we suspend the typical 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. It’s important to do this before summer because hotter temperatures can increase the potential for bacterial growth in pipes.

Common Disinfection Practice

Many water providers who use chloramine maintain their systems using this same process. NTMWD has been doing this for over 15 years, and high water quality has always been maintained.

Ongoing water testing required by the Texas Commission on Environmental Quality (TCEQ) is performed during the process and made available to the public.

Learn more about why public water systems may make a temporary change in disinfectant from the TCEQ.

Did You Know?

  • During the temporary change in disinfectant, the cities we serve may help move the blend of chloramine- and chlorine-disinfected water through the system by flushing water from fire hydrants.  Learn more about the purpose of flushing.
  • Even at 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.
  • Certain facilities such as hospitals, dialysis centers, manufacturing companies, and fish and amphibian sellers/owners need to be aware of the temporary change in disinfectant since changes in our treatment process may impact their operations. For dialysis uses, read more from the Association for the Advancement of Medical Instrumentation (AAMI) in their report on Dialysis Water and Dialysate Recommendations. For aquatic animal care, review these frequently asked questions from the CDC.
  • You can review NTMWD water quality data and information during the temporary change and year-round:

Resources for More Information: