Section 809.65. Operational evaluation levels for disinfection byproducts under Stage 2 DBP.

 

(1)   Operational evaluation . An operational evaluation shall be conducted if any of the following occurs:

(a) The sum of the two previous quarters' TTHM results plus twice the current quarter's TTHM result, divided by 4, exceeds 0.080 mg/L at any monitoring location.

(b) The sum of the two previous quarters' HAA5 results plus twice the current quarter's HAA5 result, divided by 4, exceeds 0.060 mg/L at any monitoring location.

(2)   Operational evaluation reporting . If an operational evaluation must be performed as required in sub. (1) , it shall be submitted as a written report to the department no later than 90 days after being notified of the analytical result that causes the public water system to exceed the operational evaluation level. The written report shall be made available to the public upon request.

(3)   Contents of an operational report . An operational evaluation shall include an examination of the 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 exceedances.

(4)   Limiting the scope of an operational evaluation. A water supplier may request and the department may allow the water supplier to limit the scope of the operational evaluation if the water supplier is able to identify the cause of the operational evaluation level exceedance. The request to limit the scope of the evaluation does not extend the schedule required under sub. (2) for submitting the written report. If the department approves this limited scope of evaluation, the approval shall be in writing and the water supplier shall keep the written approval with the completed report.

CR 09-073 : cr. Register November 2010 No. 659 , eff. 12-1-10; CR 15-049 : am. (1) (a), (b) Register March 2016 No. 723 , eff. 4-1-16.