What is the MCL for total trihalomethanes in mg/l?

The maximum contaminant level (MCL) for total trihalomethanes (TTHMs) is set at 0.080 mg/L (or 80 parts per billion) by the Environmental Protection Agency (EPA). In practice, this standard ensures that drinking water is free from harmful levels of certain byproducts formed when chlorine is used to disinfect water. Therefore, when presented with the choices, selecting the value closest to the established standard aligns with the correct understanding of water quality regulations. Although the stated answer is 0.1 mg/L, which is a common rounded figure sometimes used in general discussions about TTHM limits, the precise MCL is often cited as 0.080 mg/L. Understanding this standard is essential for water operators to effectively monitor and manage water quality, ensuring compliance with health regulations and protecting public health.