Section 327IAC8-2.5-4. General requirements; disinfectant residuals, disinfection byproducts, and disinfection byproducts precursors

   (a) The general requirements for disinfectant residuals, disinfection byproducts, and disinfection byproducts precursors are as follows:

(1) A CWS or an NTNCWS, which adds a chemical disinfectant to the water in any part of the drinking water treatment process, shall modify its practices to meet MCLs and MRDLs in sections 2(a) and 3(a) of this rule, respectively, and shall meet the treatment technique requirements for disinfection byproduct precursors in section 9 of this rule.

(2) A TWS that uses chlorine dioxide as a disinfectant or oxidant shall modify its practices to meet the MRDL for chlorine dioxide in section 3(a) of this rule.

  (b) Compliance dates for CWSs and NTNCWSs are as follows:

(1) A subpart H system serving a population of ten thousand (10,000) or more individuals shall comply with this section upon the effective date of this rule.

(2) A subpart H system serving a population of fewer than ten thousand (10,000) individuals and a system using only ground water not under the direct influence of surface water shall comply with this section beginning January 1, 2004.

  (c) Compliance dates for TWSs are as follows:

(1) A subpart H system serving a population of ten thousand (10,000) or more individuals and using chlorine dioxide as a disinfectant or oxidant shall comply with requirements for chlorine dioxide in this section upon the effective date of this rule.

(2) A subpart H system serving a population of fewer than ten thousand (10,000) individuals and using chlorine dioxide as a disinfectant or oxidant and a system using only ground water not under the direct influence of surface water and using chlorine dioxide as a disinfectant or oxidant shall comply with requirements for chlorine dioxide in this section beginning January 1, 2004.

  (d) A CWS or a NTNCWS regulated under subsection (a) must be operated by qualified personnel who meet the requirements specified by 327 IAC 8-12.

  (e) Notwithstanding the MRDLs in section 3 of this rule, systems may increase residual disinfectant levels in the distribution system of chlorine or chloramines, but not chlorine dioxide, to a level and for a time necessary to protect public health and to address specific microbiological contamination problems caused by circumstances, including the following:

(1) Distribution line breaks.

(2) Storm water run-off events.

(3) Source water contamination events.

(4) Cross-connection events.

(Water Pollution Control Division; 327 IAC 8-2.5-4; filed May 1, 2003, 12:00 p.m.: 26 IR 2840)