What is the MCL for total trihalomethanes in water systems using surface water?

The maximum contaminant level (MCL) for total trihalomethanes (TTHMs) in water systems using surface water is set at 0.08 mg/L. This standard is established to protect public health, as TTHMs are known byproducts of chlorination used in water treatment, and their presence in drinking water can have adverse health effects over time, including potential risks of cancer. The regulation aims to ensure that the levels of these compounds are kept within safe limits, thereby safeguarding the health of consumers relying on treated surface water supplies. Understanding this standard is essential for water system operators to maintain compliance and ensure the safety of the water supply.