R309-210-5. Microbiological Monitoring

(1) Routine Microbiological Monitoring Requirements Applicable to all public water systems (community, non-transient non-community and transient non-community).

(a) Community water systems shall monitor for total coliforms at a frequency based on the population served, as follows:

TABLE 210-1

TOTAL COLIFORM MONITORING FREQUENCY

FOR PUBLIC WATER SYSTEMS

                                      Minimum number

    Population served of samples

                                        per month

           25 to 1,000 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

    1,520,001 to 1,850,000 360

    1,850,001 to 2,270,000 390

    2,270,001 to 3,020,000 420

    3,020,001 to 3,960,000 450

    3,960,001 or more 480

     The 25 - 1,000 population figure includes public water

systems which have at least 15 service connections, but serve

fewer than 25 persons.

(b) Non-transient non-community water systems shall monitor for total coliforms as follows:

(i) A system using only ground water (except ground water under the direct influence of surface water) and serving 1,000 or fewer shall monitor each calendar quarter that the system provides water to the public.

(ii) A system using only ground water (except ground water under the direct influence of surface water) and serving more than 1,000 persons during any month shall monitor at the same frequency as a like-sized community water system, as specified in Table 210-1. The Director may reduce the monitoring frequency for any month the system serves 1,000 persons or fewer. In no case may the required monitoring be reduced to less than once per calendar quarter.

(iii) A system using surface water, in total or in part, shall monitor at the same frequency as a like-sized community water system, as specified in Table 210-1.

(iv) A system using ground water under the direct influence of surface water shall monitor at the same frequency as a like-sized community water system, as specified in Table 210-1. The system shall begin monitoring at this frequency beginning six months after the Director determines that the ground water is under the direct influence of surface water.

(c) Non-community water systems shall monitor for total coliforms as specified in R309-210-5(1)(b).

(d) The samples shall be collected at points which are representative of water throughout the distribution system according to a written sampling plan. This plan is subject to the approval of the Director.

(e) A public water system shall collect samples at regular time intervals throughout the month, except that a system which uses only ground water (except ground water under the direct influence of surface water) and serves 4,900 persons or fewer, may collect all required samples on a single day if they are taken from different sites.

(f) A public water system that uses inadequately treated surface water or inadequately treated ground water under the direct influence of surface water shall collect and analyze for total coliforms at least one sample each day the turbidity level of the source water exceeds 1 NTU. This sample shall be collected near the first service connection from the source. The system shall collect the sample within 24 hours of the time when the turbidity level was first exceeded. The sample shall be analyzed within 30 hours of collection. Sample results from this coliform monitoring shall be included in determining total coliform compliance for that month. The Director may extend the 24 hour limitation if the system has a logistical problem that is beyond the system's control. In the case of an extension the Director shall specify how much time the system has to collect the sample.

(2) Procedures if a Routine Sample is Total Coliform-Positive

(a) Repeat sampling -

The water system shall collect a set of repeat samples within 24 hours of being notified of the total coliform-positive sample result. The number of repeat samples required to be taken is specified in Table 210-2. The Director may extend the 24 hour limitation if the system has a logistical problem that is beyond its control. In the case of an extension the Director shall specify how much time the system has to collect the repeat samples.

TABLE 210-2

REPEAT AND ADDITIONAL SAMPLE MONITORING FREQUENCY

Population # Routine # Repeats for # Samples in

Served by Samples each Total- ADDITION to the

the system per month Coliform Routine samples

                          Positive sample the following

                          Within 24 hours month

25-1000/See 1 4 4

Note 1 below

1000-2500 2 3 3

2501-3300 3 3 2

3301-4100 4 3 1

greater

than 4100 5 or more 3 No additional samples

                                            required. Refer to

                                            Table 210-1 for # of

                                            Routine samples

    NOTE 1: The population category 25 - 1000 includes all

non-transient non-community and non-community water systems.

Non-transient non-community and non-community systems are only

are required to sample once per calendar quarter on a routine

basis for those quarters the system is in operation.

    Repeat and Additional Routine samples are only required

if a Routine Sample is Total Coliform-Positive.

(b) Repeat sampling locations -

The system shall collect the repeat samples from the following locations:

(i) One from the original sample site;

(ii) One within 5 service connections upstream;

(iii) One within 5 service connections downstream;

(iv) If required, one from any site mentioned above.

If a total coliform-positive sample is at the end of the distribution system, or next to the end of the distribution system, the Director may waive the requirement to collect at least one repeat sample upstream or downstream of the original sampling site.

(c) The system shall collect all repeat samples on the same day, except that the Director may allow a system with a single service connection to collect the required set of repeat samples on consecutive days.

(d) Additional repeat samples - If one or more repeat samples in a set is total coliform-positive, the system shall collect an additional set of repeat samples as specified in (a), (b) and (c) of this subsection. The additional repeat samples shall be collected within 24 hours of being notified of the positive result, unless the Director extends the time limit because of a logistical problem. The system shall repeat this process until either total coliforms are not detected in one complete set of repeat samples or the system determines that the total coliform MCL has been exceeded and notifies the Director and begins the required public notification.

(e) If a system collecting fewer than five routine samples per month has one or more total coliform-positive samples and the Director does not invalidate the sample under R309-210-5(4), it shall collect at least five routine samples during the next month the system provides water to the public. Refer to Table 210-2 for the number of additional samples required.

(i) The Director may waive the requirement to collect five routine samples the next month the system provides water to the public if the Director has determined why the sample was total coliform-positive and establishes that the system has corrected the problem or will correct the problem before the end of the next month the system serves water to the public. In this case:

(A) The Director shall document this decision in writing; and

(B) The Director or his representative shall sign the document; and

(C) The Director will make the document available to the EPA and the public.

(ii) The Director cannot waive the additional samples in the following month solely because all repeat samples are total coliform-negative.

(iii) If the additional samples in the following month are waived, a system shall still take the minimum number of routine samples required in Table 210-1 of R309-210-5(1) before the end of the next month and use it to determine compliance with the total coliform MCL.

(f) Samples to be included in calculations - Results of all routine and repeat samples not invalidated in writing by the Director shall be included in determining compliance with the total coliform MCL.

(g) Samples not to be included in calculations - Special purpose and investigative samples, such as those taken to determine the efficiency of disinfection practices following such operations as pipe replacement or repair, may not be used to determine compliance with the MCL for total coliforms. These samples shall be identified as special purpose or investigative at the time of collection.

(3) Response to violation

(a) A public water system which has exceeded the MCL for total coliforms as specified in R309-200-5(6) shall report the violation to the Director no later than the end of the next business day after it learns of the violation, and notify the public in accordance with R309-220.

(b) A public water system which has failed to comply with a coliform monitoring requirement shall report the monitoring violation to the Director within ten days after the system discovers the violation and notify the public in accordance with R309-220.

(4) Invalidation of Total Coliform-Positive Samples

An invalidated total coliform-positive sample does not count towards meeting the minimum monitoring requirements of R309-210-5(1) and R309-210-5(2). A total coliform-positive sample may not be invalidated solely on the basis of all repeat samples being total coliform-negative.

(a) The Director may invalidate a total coliform-positive sample only if one of the following conditions are met:

(i) The laboratory establishes that improper sample analysis caused the total coliform-positive result; or

(ii) On the basis of the results of repeat samples collected as required in R309-210-5(2), the total coliform-positive sample resulted from a non-distribution system plumbing problem on the basis that all repeat samples taken at the same tap as the original total coliform-positive are total coliform-positive, but all repeat samples within five service connections are total coliform-negative; or

(iii) Substantial grounds exist to establish that the total coliform-positive result is due to a circumstance or condition which does not reflect water quality in the distribution system. In this case:

(A) The Director shall document this decision in writing; and

(B) The Director or his representative shall sign the document; and

(C) The Director will make the document available to the EPA and the public. The system shall still collect the required repeat samples as outlined in R309-210-5(2) in order to determine compliance with the MCL.

(b) A laboratory shall invalidate a total coliform sample (unless total coliforms are detected) if the results are indeterminate because of possible interference. A system shall collect and have analyzed, another total coliform sample from the same location as the original sample within 24 hours of being notified of the indeterminate result. The system shall continue to resample within 24 hours of notification of indeterminate results and have the samples analyzed until a valid sample result is obtained. The 24-hour time limit may be waived by the Director on a case-by-case basis if the system has logistical problems beyond its control. Interference for each type of analysis is listed below.

(i) The sample produces a turbid culture in the absence of gas production when using an analytical method where gas formation is examined.

(ii) The sample produces a turbid culture in the absence of an acid reaction when using the Presence-Absence Coliform Test.

(iii) The sample exhibits confluent growth or produces colonies too numerous to count when using an analytical method using a membrane filter.

(5) Fecal coliforms/Escherichia coli (E. coli) testing

(a) If any routine sample, repeat sample or additional sample is total coliform-positive, the system shall have the total coliform-positive culture medium analyzed to determine if fecal coliforms are present. The system may test for E. coli in lieu of fecal coliforms.

(b) Notification of Director and public - If fecal coliforms or E. coli are confirmed present (as per R309-200-5(6)(b)), the system shall notify the Director by the end of the day when the system is notified of the test results. If the system is notified after the Division of Drinking Water has closed, the system shall notify the Director before the close of the next business day and begin public notification using the mandatory health effects language R309-220) within 72 hours.

(c) The Director may allow a system to forego the analysis for fecal coliforms or E. coli, if the system assumes that the total coliform positive sample is fecal coliform-positive or E. coli-positive. The system must notify the Director of this decision and begin the required public notification.

(6) Best Available Technology

The Director may require an appropriate treatment process using the best available technology (BAT) in order to bring the water into compliance with the maximum contaminant level for microbiological quality. The BAT will be determined by the Director.