What is the maximum contaminant level for total trihalomethanes (TTHM) in the United States?

The maximum contaminant level (MCL) for total trihalomethanes (TTHM) in the United States is set at 0.080 mg/l. This regulatory limit is established by the Environmental Protection Agency (EPA) to protect public health, as TTHMs can form when chlorine or other disinfectants used in drinking water treatment react with organic materials in the water. Chronic exposure to elevated levels of TTHMs has been linked to adverse health effects, including an increased risk of cancer and potential reproductive issues.

The MCL is important because it helps ensure that drinking water remains safe for consumption, balancing the need for effective disinfection while minimizing risks associated with byproducts like TTHMs. Maintaining levels below this threshold promotes public safety and fosters trust in water treatment practices.

Understanding MCLs and their significance helps water operators ensure compliance with regulations and safeguard the health of the communities they serve.