Section 327IAC8-2-8. Collection of samples for total coliform bacteria testing

   (a) Public water systems must collect total coliform samples at sites that are representative of water throughout the distribution system according to a written sample siting plan approved by the commissioner.

  (b) The monitoring frequency for total coliforms for community water systems is based on the population served by the system and shall be as follows unless the commissioner determines that more frequent sampling is appropriate:

TOTAL COLIFORM MONITORING FREQUENCY FOR COMMUNITY WATER SYSTEMS
Population Served			Minimum Number of Samples Per Month
25		to 1,0001	1
1,001		to 2,500	2
2,501		to 3,300	3
3,301		to 4,100	4
4,101		to 4,900	5
4,901		to 5,800	6
5,801		to 6,700	7
6,701		to 7,600	8
7,601		to 8,500	9
8,501		to 12,900	10
12,901		to 17,200	15
17,201		to 21,500	20
21,501		to 25,000	25
25,001		to 33,000	30
33,001		to 41,000	40
41,001		to 50,000	50
50,001		to 59,000	60
59,001		to 70,000	70
70,001		to 83,000	80
83,001		to 96,000	90
96,001		to 130,000	100
130,001		to 220,000	120
220,001		to 320,000	150
320,001		to 450,000	180
450,001		to 600,000	210
600,001		to 780,000	240
780,001		to 970,000	270
970,001		to 1,230,000	300
1,230,001		to 1,520,000	330
1Includes public water systems that have at least fifteen (15) service connections but serve fewer than twenty-five (25) persons.

If a community water system serving twenty-five (25) to one thousand (1,000) persons has no history of total coliform contamination in its current configuration and a sanitary survey conducted in the past five (5) years shows that the system is supplied solely by a protected ground water source and is free of sanitary defects, the commissioner may reduce the monitoring frequency specified in this subsection, in writing, except that in no case may the commissioner reduce the monitoring frequency to less than one (1) sample per quarter.

  (c) The monitoring frequency for total coliforms for noncommunity water systems is as follows:

(1) A noncommunity water system:

(A) using only ground water (except ground water under the direct influence of surface water, as defined in section 1(36) of this rule); and

(B) serving one thousand (1,000) or fewer persons;

must monitor each calendar quarter that the system provides water to the public, except that the commissioner may reduce this monitoring frequency, in writing, if a sanitary survey shows that the system is free of sanitary defects. Beginning June 29, 1994, the commissioner shall not reduce the monitoring frequency for a noncommunity water system using only ground water (except ground water under the direct influence of surface water, as defined in section 1(36) of this rule) and serving one thousand (1,000) or fewer persons to less than once per year.

(2) A noncommunity water system:

(A) using only ground water (except ground water under the direct influence of surface water, as defined in section 1(36) of this rule); and

(B) serving more than one thousand (1,000) persons during any month;

must monitor at the same frequency as a like-sized community water system, as specified in subsection (b), except the commissioner may reduce this monitoring frequency, in writing, for any month the system serves one thousand (1,000) or fewer persons. The commissioner shall not reduce the monitoring frequency to less than once per year. For systems using ground water under the direct influence of surface water, subdivision (4) applies.

(3) A noncommunity water system using surface water, in total or in part, must monitor at the same frequency as a like-sized community water system, as specified in subsection (b), regardless of the number of persons it serves.

(4) A noncommunity water system using ground water under the direct influence of surface water, as defined in section 1(36) of this rule, must monitor at the same frequency as a like-sized community water system specified in subsection (b). The system must begin monitoring at this frequency beginning six (6) months after the commissioner determines that the ground water is under the direct influence of surface water.

  (d) The public water system must collect samples at regular time intervals throughout the month, except a system that:

(1) uses only ground water (except ground water under the direct influence of surface water, as defined in section 1(36) of this rule); and

(2) serves four thousand nine hundred (4,900) persons or fewer;

may collect all required samples on a single day if they are taken from different sites.

  (e) Special purpose samples, such as those taken to determine whether disinfection practices are sufficient following pipe placement, replacement, or repair, shall not be used to determine compliance with the MCL for total coliforms in section 7 of this rule. Repeat samples taken under section 8.1 of this rule:

(1) are not considered special purpose samples; and

(2) must be used to determine compliance with the MCL for total coliforms required by section 7 of this rule.

Any sample not designated as special purpose before analysis by the laboratory shall be used to determine compliance with the MCL for total coliforms in section 7 of this rule.

  (f) A total coliform-positive sample invalidated under this subsection does not count towards meeting the minimum monitoring requirements of this section. The total coliform-positive sample may be invalidated only if the following conditions are met:

(1) The laboratory establishes that improper sample analysis caused the total coliform-positive result.

(2) The commissioner, on the basis of the results of repeat samples collected as required by section 8.1(a) through 8.1(d) of this rule, determines that the total coliform-positive sample resulted from a domestic or other nondistribution system plumbing problem. The commissioner cannot invalidate a sample on the basis of repeat sample results unless all repeat samples collected:

(A) at the same tap as the original total coliform-positive sample are also total coliform-positive; and

(B) within five (5) service connections of the original tap are total coliform-negative.

For example, the commissioner cannot invalidate a total coliform-positive sample on the basis of repeat samples if all the repeat samples are total coliform-negative or if the public water system has only one (1) service connection.

(3) The commissioner has substantial grounds to believe that a total coliform-positive result is due to a circumstance or condition that does not reflect water quality in the distribution system. In this case, the system must still collect all repeat samples required by section 8.1(a) through 8.1(d) of this rule and use them to determine compliance with the MCL for total coliforms in section 7 of this rule. To invalidate a total coliform-positive sample under this subsection, the decision must be documented, in writing, and approved and signed by the supervisor of the state official who recommended the decision. The commissioner must make this document available to EPA and the public. The written documentation must state the following:

(A) The specific cause of the total coliform-positive sample.

(B) What action the system has taken, or will take, to correct this problem.

The commissioner may not invalidate a total coliform-positive sample solely on the grounds that all repeat samples are total coliform-negative.

(4) A laboratory must invalidate a total coliform sample, unless total coliforms are detected, if the sample:

(A) produces a turbid culture in the absence of:

(i) gas production using an analytical method where gas formation is examined, for example, the multiple-tube fermentation technique; or

(ii) an acid reaction in the presence-absence (P-A) coliform test; or

(B) exhibits confluent growth or produces colonies too numerous to count with an analytical method using a membrane filter, for example, the membrane filter technique.

If a laboratory invalidates a sample because of such interference, the system must collect another sample from the same location as the original sample within twenty-four (24) hours of being notified of the interference problem and have it analyzed for the presence of total coliforms. The system must continue to resample within twenty-four (24) hours and have the samples analyzed until it obtains a valid result. The commissioner may waive the twenty-four (24) hour time limit on a case-by-case basis.

(Water Pollution Control Division; 327 IAC 8-2-8; filed Sep 24, 1987, 3:00 p.m.: 11 IR 707; filed Dec 28, 1990, 5:10 p.m.: 14 IR 1019; errata filed Jan 9, 1991, 2:30 p.m.: 14 IR 1070; errata filed Aug 6, 1991, 3:45 p.m.: 14 IR 2258; filed Apr 12, 1993, 11:00 a.m.: 16 IR 2155; filed Jul 23, 2001, 1:02 p.m.: 24 IR 3965; filed Jul 13, 2007, 11:58 a.m.: 20070808-IR-327060044FRA)