Frequent Questions

If a system is required to take 8 high TTHM samples, can all 8 samples be taken at the same location?

No, the monitoring plan must identify 8 different sites with the 8 highest historical TTHM levels. These sites also must not be the same location as where the system currently takes their required Stage 1 DBPR TTHM/HAA5 samples.

For additional guidance on the Stage 2 Disinfectants and Disinfection Byproducts rule please visit

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