Frequent Questions

If a CWS had one total trihalomethane (TTHM) detect above 80 parts per billion during the year, but the annual average was below the MCL, do they need to include the health effects statement?

Community water systems that detect TTHM above 80 parts per billion (0.80 mg/L), but below the MCL 80 parts per billion as an annual average, must include health effects language for TTHMs (CFR Section 141.154(e)).

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