NTMWD Annual Chlorine Maintenance

North Texas Municipal Water District (NTMWD) the water supplier for the City and most of the region, will temporarily change the disinfectant in its water treatment process annually, usually in March and April. The annual, routine change is necessary to maintain the regional system and year-round water quality.

What This Is & Why It's Needed

During the temporary change, NTMWD suspends adding ammonia (learn more about the normal two-step process) and uses only free chlorine to keep the water disinfected as it travels through pipes. This annual, temporary change is also known as chlorine maintenance, takes advantage of chlorine's effectiveness at eliminating microorganisms and gives our water system a "deep cleaning."

Change in Taste & Odor

While chlorine levels are consistent with the rest of the year, the temporary suspension of ammonia can make the smell or taste more noticeable, however, the water remains safe to drink and use. For those who are sensitive to the taste, odor, and skin contact, there are simple steps that can make it less noticeable. NTMWD has provided the following information to help minimize those effects during the annual chlorine maintenance period.

Special Considerations

Facilities such as hospitals, dialysis centers, manufacturing companies, and fish and amphibian sellers/owners should be aware of how water disinfected with chloramine and chlorine may impact their operations. Resources are available such as:


To help move the chlorine-disinfected water through the system faster during this four week period, City staff will often flush water out of fire hydrants. Frequent flushing helps maintain the system, ensure high water quality, and reduce the chlorine odor and taste.

Our Water Is Safe - Here's How We Know

Meets or Exceeds State & Federal Standards

The Environmental Protection Agency (EPA) creates federal water quality guidelines based on thorough, peer-reviewed research. Every treatment process used by the City of Melissa and NTMWD meets EPA safety criteria. The following are additional resources regarding the safety of this common disinfection process:

Monitoring & Reporting

Thousands of water quality tests are performed annually by the City of Melissa, the NTMWD, and the Texas Commission on Environmental Quality. These tests verify that Melissa's water meets all federal and state requirements for health and safety. The City of Melissa is committed to water safety and we recommend our customers review the water quality information presented annually in the City's Consumer Confidence Report (CCR) which must be filed with TCEQ annually. Should you have any questions regarding this report, please email the Director of Public Works Jeff Cartwright.

Questions About the Temporary Disinfectant Process

More details about the annual maintenance can be found in the Frequently Asked Questions with additional resources available online. Any questions about this process should be emailed to NTMWD staff or call 972-442-5405.

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