Frequently Asked Questions

NTMWD has a state-certified laboratory that analyzes over a quarter million water quality samples a year - hundreds of tests daily - to ensure water quality meets or surpasses safe water requirements. The District laboratory tests water in our system and provides testing services for Member Cities and Customer entities. Additionally, the TCEQ conducts independent tests in the NTMWD and city systems to ensure compliance with state and federal regulations. View the results on the Water Quality Reports page.

View the monthly and annual water quality reports. NTMWD will also post chlorine levels weekly during the temporary disinfectant change period and results from monthly testing for disinfection by-products.

NTMWD tests for the concentrations of chlorine at our treatment plants and at certain points in the transmission system every 15 minutes. We added even more sample locations in 2019. We also test once a week at the delivery points at which the cities we serve collect the water to pipe to their customers. All of this testing occurs year-round and is reported to the TCEQ. The cities we serve also sample and monitor the water that is distributed to their customers. Those tests are taken and measured daily in the field. Additionally, in 2018 during the temporary change in disinfectant period TCEQ collected 117 samples from 31 public water systems that deliver NTMWD water.

TCEQ conducts routine water sampling in the NTMWD and city systems through an independent laboratory to confirm water quality compliance with state and federal standards. The cities we serve also collect their own water samples, which are analyzed in NTMWD's state-certified laboratory and reported to TCEQ.

The EPA requires water treatment facilities to maintain a minimum chlorine level of 0.2 milligrams per liter (mg/l)-or parts 0.2 parts per million (ppm)-during the routine change in disinfectant, and levels must not exceed a maximum running average of 4 mg/l (or 4 ppm). NTMWD system's chlorine levels during the disinfection change period are consistent with the rest of the year. After the treated water leaves the plant, the chlorine begins to dissipate as it travels long distances to the tap.

TCEQ confirms that the District meets or surpasses all safe water requirements.

According to the TCEQ, "A normal level for drinking water disinfection can range from 1 part per million to 4 parts per million which is similar to chlorine levels found in swimming pools." However, pool test kits are not a reliable method to test drinking water. According to the Centers for Disease Control (CDC), pool kits take inaccurate readings over time; do not provide reliable, quantitative results; and lack calibration and standardization. You can learn more from CDC.

The EPA regulates DBPs (Trihalomethanes or THMs and Haloacetic acids or HAA5) at levels that current research considers safe. The TCEQ tests quarterly in the cities we serve for the regulated DBPs to confirm compliance with EPA's regulations. NTMWD voluntarily began testing monthly for DBPs in late 2018. This testing is above and beyond what is required. Results show that NTMWD meets or surpasses the standards required for drinking water safety.

• Review water quality information and Consumer Confidence Reports on your city or local water utility website and contact them with any questions (agency who sends your water bill).
• View NTMWD water quality information, including monthly reports and the annual Consumer Confidence Report.
• Contact NTMWD to learn how the water is treated and distributed to your city (local provider) or call 972-442-5405.

If you wish to perform additional testing, use a state-certified laboratory to provide sampling instructions, containers, and ensure accurate results. You can find an accredited laboratory in Texas through TCEQ. Consumers should be cautious of and do research on any private companies offering free testing to sell products or services.

Pool test kits are not a reliable method to test drinking water. According to the Centers for Disease Control (CDC), pool kits take inaccurate readings over time; do not provide reliable, quantitative results; and lack calibration and standardization. You can learn more from CDC.

Beware of claims from companies advocating filtration for water safety. NTMWD's water is safe to drink without filtration. Some filters can help dissipate chlorine odor, taste and skin sensitivities. Look for filters labeled with NSF International (NSF/ ANSI) approval. DrinkTap.org has some additional filter guidelines.