(a) Following the completion of initial source water monitoring under section 5-1.81(a)(1) of this Subpart, a system that plans to make a significant change to its disinfection practice, as defined in subdivision (b) of this section, shall develop disinfection profiles and calculate disinfection benchmarks for Giardia lamblia and viruses, in accordance with 40 CFR 141.709. Prior to changing the disinfection practice, the system shall notify the State and shall include in this notice the following information:

1. (1) a completed disinfection profile and disinfection benchmark for Giardia lamblia and viruses prepared as described in 40 CFR 141.709;
2. (2) a description of the proposed change in disinfection practice;
3. (3) an analysis of how the proposed change will affect the current level of disinfection.

(b) Significant changes to disinfection practice are defined as follows:

1. (1) changes to the point of disinfection;
2. (2) changes to the disinfectant(s) used in the treatment;
3. (3) changes to the disinfection process; or
4. (4) any other modification identified by the State as a significant change to disinfection practice.