Section 302.505  Fecal Coliform

Based on a minimum of five samples taken over not more than a 30-day period, fecal coliform must not exceed a geometric mean of 20 per 100 ml in the Open Waters of Lake Michigan as defined in Section 302.501.  The remaining waters of the Lake Michigan Basin must not exceed a geometric mean of 200 per 100 ml, nor may more than 10% of the samples during any 30-day period exceed 400 per 100 ml.

(Source:  Amended at 47 Ill. Reg. 4437, effective March 23, 2023)