R 325.10719l Disinfection byproducts: operational evaluation levels.

Rule 719l. (1) The community or nontransient noncommunity water supply that is subject to disinfection byproducts requirements of R 325.10610d has exceeded the operational evaluation level at a monitoring location where the sum of the 2 previous quarters' TTHM results plus twice the current quarter's TTHM result, divided by 4 to determine an average, exceeds 0.080 mg/L, or where the sum of the 2 previous quarters' HAA5 results plus twice the current quarter's HAA5 result, divided by 4 to determine an average, exceeds 0.060 mg/L. (2) Both of the following provisions apply to operational evaluations: (a) A supply that exceeds the operational evaluation level shall conduct an operational evaluation and submit a written report of the evaluation to the department not later than 90 days after being notified of the analytical result that causes the supply to exceed the operational evaluation level. The written report shall be made available to the public upon request. (b) The operational evaluation shall include an examination of system treatment and distribution operational practices, including storage tank operations, excess storage capacity, distribution system flushing, changes in sources or source water quality, and treatment changes or problems that may contribute to TTHM and HAA5 formation and what steps could be considered to minimize future exceedences. Both of the following provisions apply to limiting the scope of the operational evaluation: (i) The supply may request and the department may allow the supply to limit the scope of the evaluation if the supply is able to identify the cause of the operational evaluation level exceedance. (ii) The request to limit the scope of the evaluation does not extend the schedule in subdivision (a) of this subrule for submitting the written report. The department shall approve this limited scope of evaluation in writing and the supply shall keep that approval with the completed report.