1. (a) A PWS owner shall conduct an assessment in accordance with Env-Dw 720.07 if an assessment is triggered as specified in (b) or (c) below.

2. (b) The level 1 assessment shall be triggered if:

   1. (1) For a PWS collecting fewer than 40 samples per month, the system has 2 or more total coliform-positive samples in the same month;
   2. (2) For a PWS collecting 40 or more samples per month, more than 5.0% of the samples collected during a month are total coliform-positive; or
   3. (3) The PWS fails to take every required repeat sample after any single total coliform-positive sample result.

3. (c) The level 2 assessment shall be triggered if:

   1. (1) An E. coli MCL violation as specified in Env-Dw 702.02 occurs; or

   2. (2) A second level 1 assessment is triggered within 12 months of a prior level 1 or level 2 assessment, unless the department has:

      1. a. Identified a likely reason that the samples that caused the first level 1 treatment technique trigger were total coliform-positive; and
      2. b. Determined that the owner has corrected the problem.

Source. #10771, eff 2-1-15; ss by 14343, eff 8-22-25, EXPIRES: 8-22-35