Section 304.224  Effluent Disinfection

From March 1 through November 30, effluents discharged to the Primary Contact Recreation waters listed in 35 Ill. Adm. Code 303.220 must not exceed 400 fecal coliform colony forming units (CFU) per 100 ml if fewer than 10 samples are taken in a month.  If 10 or more samples are taken in a month, fecal coliform must not exceed a 30-day geometric mean of 200 CFU per 100 ml, and must not exceed 400 CFU per 100 ml in more than 10% of the samples during any 30-day period.  All effluents in existence on or before February 3, 2012 must meet these standards by March 1, 2016.  All new discharges must meet these standards upon the initiation of discharge. 

(Source:  Amended at 47 Ill. Reg. 4601, effective March 23, 2023)