Frequent Questions

A PWS has exceeded the MCL of 80 ppb for total trihalomethanes (TTHMs) for calendar year 2002. What is the public notification requirement?

Exceeding the MCL for TTHMs is a Tier 2 violation. Public notification for a Tier 2 violation must be issued as soon as practical but within 30 days after a violation is discovered. For any unresolved Tier 2 violation, a PWS must repeat the notice every three months or until the violation is resolved, unless the primacy agency makes a determination that circumstances warrant a different repeat frequency. This may never be less frequent than once per year (40 CFR 141.203(b)). Additional guidance, including public notice templates, is available in The Public Notification Handbook (EPA816-R-00-010, June 2000) available at
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