ARNOLD AIR FORCE BASE, Tenn. -- Our water system recently violated a drinking water standard. Although this incident was not an emergency, as our customers, you have a right to know what happened and what we are doing to correct this situation.
We routinely monitor for the presence of drinking water contaminants. During July 1 through Sept. 30, 2025, compliance period, the water system’s locational running annual average (LRAA) at site # 201, base commissary; bldg. 125 for total trihalomethanes (TTHMs) has been calculated to be 0.10535 mg/L. This value exceeds the maximum contaminant level of 0.080 mg/L set for TTHMs.
What should I do?
- There is nothing you need to do. You do not need to boil your water or take other corrective actions. If a situation arises where the water is no longer safe to drink, you will be notified within 24 hours.
- If you have a severely compromised immune system, have an infant, are pregnant, or are elderly, you may be at increased risk and should seek advice from your health care providers about drinking this water.
What does this mean?
This is not an emergency. If it had been an emergency, you would have been notified within 24 hours.
TTHMs are four volatile organic chemicals which form when disinfectants react with natural organic matter in the water. Disinfectants are used to minimize the risk of microbial contaminants in drinking water. The EPA considers microbial contaminants as the greatest risk to the public.
People who drink water containing trihalomethanes in excess of the MCL over many years may experience problems with their liver, kidneys, or central nervous system, and may have an increased risk of getting cancer.
What is being done?
The TTHM levels for the fourth quarter were exceeded due to a malfunction of the chlorine dioxide generator at the water treatment plant. The manufacturer of this equipment has been issued emergency purchase orders but has repeatedly failed to provide service. During this period, Arnold AFB switched to chlorine feed to disinfect the water entering the plant. Chlorine, unlike chlorine dioxide, allows formation of TTHMs. Arnold AFB has restored the chlorine dioxide generator to service and is pursuing an alternate supplier of critical equipment.
For more information, call the Arnold AFB bioenvironmental engineer at 931-454-6232.