Authority: IC 13-14-8; IC 13-18-12-4

Affected: IC 13-18-12

Sec. 30. "pH" means the logarithm of the reciprocal of hydrogen ion concentration measured at twenty-five (25) degrees Centigrade (seventy-seven (77) degrees Fahrenheit) or measured at another temperature and then converted to an equivalent value at twenty-five (25) degrees Centigrade (seventy-seven (77) degrees Fahrenheit).

(Water Pollution Control Division; 327 IAC 7.1-2-30; filed Jul 8, 2002, 2:01 p.m.: 25 IR 3721; readopted filed Jun 4, 2008, 11:07 a.m.: 20080702-IR-327080207BFA; readopted filed Jul 30, 2014, 4:04 p.m.: 20140827-IR-327140189BFA; readopted filed May 27, 2020, 11:52 a.m.: 20200624-IR-327200186BFA; filed Mar 3, 2022, 10:40 a.m.: 20220330-IR-327140029FRA; readopted filed Oct 18, 2024, 1:57 p.m.: 20241113-IR- 327230810RFA)