Section R. 325.10719k - Disinfection byproducts; conditions requiring increased monitoringRule 719k.
(1) A community or nontransient noncommunity water supply that is subject to disinfection byproducts requirements of R 325.10610d and that is required to monitor at a particular location annually or less frequently than annually under routine monitoring in R 325.10719h or reduced monitoring in R 325.10719j shall increase monitoring to dual sample sets once per quarter, taken every 90 days, at all locations if a TTHM sample is greater than 0.080 mg/L or a HAA5 sample is greater than 0.060 mg/L at any location.(2) The supply is in violation of the MCL when the LRAA exceeds the MCLs in R 325.10610 (2), calculated based on 4 consecutive quarters of monitoring, or the LRAA calculated based on fewer than 4 quarters of data if the MCL would be exceeded regardless of the monitoring results of subsequent quarters. The supply is in violation of the monitoring requirements for each quarter that a monitoring result would be used in calculating an LRAA if the supply fails to monitor.(3) The supply may return to routine monitoring once the supply has conducted increased monitoring for not less than 4 consecutive quarters and the LRAA for every monitoring location is less than or equal to 0.060 mg/L for TTHM and less than or equal to 0.045 mg/L for HAA5.Mich. Admin. Code R. 325.10719k