Section 302.503  pH

pH must be within the range of 7.0 to 9.0, except due to natural causes, in the Open Waters of Lake Michigan as defined at Section 302.501.  Other waters of the Basin must be within the range of 6.5 to 9.0 except due to natural causes.

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