What are the possible health risks of TTHM in my water?

Some people who drink water containing TTHM above the MCL over many years may experience problems with their liver, kidneys, or central nervous system and may have an increased risk of developing certain types of cancer.  Those with a severely compromised immune system, caring for an infant, pregnant, or elderly may be at increased risk.

Consumption of water with TTHM levels somewhat above the MCL for limited durations, as is the case with our water, while corrective actions are being taken to lower the levels, is not likely to significantly increase risks of adverse health effects for most people.  Cancer risks generally accrue over lifetimes and very long periods of exposure. For disinfectant byproducts like TTHM, risks are typically calculated with a daily average of drinking 2 liters of water over a lifetime of 70 years. Research on the connections between Total THM exposures and these health risks is underway.  

Water that meets the total THMs guideline is considered safe for all domestic uses, including drinking, bathing, showering, and food preparation.  The risk of illness from TTHM is much lower than that of drinking water that has not undergone disinfection. 

Show All Answers

1. What are Total Trihalomethanes (TTHM)?
2. What are the standards for TTHM in my drinking water?
3. What are the results of the TTHM samplings in my local drinking water?
4. What can cause elevated levels of TTHM?
5. What are the possible health risks of TTHM in my water?
6. What actions is the Public Utilities Department taking to reduce the TTHM in our water?
7. Why do we add disinfectant to our water?
8. Where can I get additional information?