Section 327 IAC 8-2-8.8 - Monitoring requirements; PWSs that provide filtration treatmentAuthority: IC 13-13-5; IC 13-14-8-2; IC 13-14-8-7; IC 13-18-3-1; IC 13-18-3-2; IC 13-18-16-8; IC 13-18-16-9
Affected: IC 13-18-2; IC 13-18-16
Sec. 8.8.
(a) A PWS that:(1) uses: (A) a surface water source; or(B) a ground water source under the influence of surface water; and(2) provides filtration treatment; must monitor in accordance with this section beginning June 29, 1993, or when filtration is installed, whichever is later.(b) Turbidity measurements as required by section 8.5 of this rule must be performed on representative samples of the PWS's filtered water every four (4) hours (or more frequently) that the PWS serves water to the public. A PWS may substitute continuous turbidity monitoring for grab sample monitoring if the PWS validates the continuous measurement for accuracy on a regular basis and obtains approval from the commissioner. The commissioner may reduce the turbidity sampling frequency to once per day if the commissioner determines that less frequent monitoring is sufficient to indicate effective filtration performance for the following: (1) Any PWS using: (A) slow sand filtration;(B) filtration treatment other than conventional treatment;(C) direct filtration; or(D) diatomaceous earth filtration.(2) A PWS serving five hundred (500) or fewer persons, regardless of the type of filtration treatment used.(c) The residual disinfectant concentration of the water entering the distribution system must meet the following: (1) Requirements including the following: (A) Be monitored continuously.(B) The lowest residual disinfectant concentration value must be recorded each day.(2) Exceptions, if applicable, to subdivision (1) as follows:(A) If there is a failure in the continuous monitoring equipment, the PWS must conduct sampling as follows: (i) Grab sampling every four (4) hours may be conducted in lieu of continuous monitoring.(ii) Sampling under item (i) may occur for not more than two (2) working days following the failure of the equipment.(B) A PWS serving three thousand three hundred (3,300) or fewer persons may take grab samples in lieu of providing continuous monitoring on an ongoing basis at the frequencies each day prescribed as follows: | PWS size by population | Samples per day* |
| [LESS THAN]500 | 1 |
| 501-1,000 | 2 |
| 1,001-2,500 | 3 |
| 2,501-3,300 | 4 |
*The day's samples cannot be taken at the same time. The sampling intervals are subject to review and approval by the commissioner.
(3) If at any time the residual disinfectant concentration falls below two-tenths (0.2) milligram per liter in a PWS using grab sampling under subdivision (2) in lieu of continuous monitoring under subdivision (1), the PWS must take a grab sample every four (4) hours until the residual disinfectant concentration is equal to or greater than two-tenths (0.2) milligram per liter.(d) The residual disinfectant concentration must be measured according to the following: (1) At least at the same points in the distribution system and at the same time as total coliforms are sampled in accord with the following:(A) Until March 31, 2016, as specified in section 8 of this rule.(B) Beginning April 1, 2016, as specified in 40 CFR 141.854 through 40 CFR 141.858 *.(2) At points other than the total coliform sampling points under subdivision (1) for a PWS that uses both a: (A) surface water source or a ground water source under direct influence of surface water; and(B) ground water source; if the commissioner determines that the sampling points other than those under subdivision (1) are more representative of treated (disinfected) water quality within the distribution system.
Heterotrophic bacteria, measured as heterotrophic plate count (HPC), as specified in section 8.7(3) of this rule, may be measured in lieu of residual disinfectant concentration.
(e) If the commissioner determines, based on site-specific considerations, that a PWS:(1) has no means for having a sample transported and analyzed for HPC by a certified laboratory under the requisite time and temperature conditions specified in section 8.7(3) of this rule; and(2) is providing adequate disinfection in the distribution system; the requirements of subsection (d) do not apply to that PWS. *These documents are incorporated by reference. Copies may be obtained from the Government Publishing Office, www.gpo.gov, or are available for review at the Indiana Department of Environmental Management, Office of Legal Counsel, Indiana Government Center North, 100 North Senate Avenue, Thirteenth Floor, Indianapolis, Indiana 46204.
Water Pollution Control Board; 327 IAC 8-2-8.8; filed Dec 28, 1990, 5:10 p.m.: 14 IR 1026; filed Apr 12, 1993, 11:00 a.m.: 16 IR 2162Filed 1/18/2017, 1:01 p.m.: 20170215-IR-327140059FRA