(a) The MCL is based on the presence or absence of total coliforms in a sample, rather than coliform density.

(b) Any fecal coliform-positive repeat sample or E. coli-positive repeat sample, or any total coliform-positive repeat sample following a fecal coliform-positive or E. coli-positive routine sample constitutes a violation of the MCL for total coliforms. For purposes of the public notification requirements in Section 391-3-5-.32, this is a violation that may pose an acute risk to health.

(c) A public water system must determine compliance with the MCL for total coliforms in paragraphs (a) and (b) of this Section for each month in which it is required to monitor for total coliforms.

(a) Public water systems must collect total coliform samples at sites which are representative of water throughout the distribution system according to a written sample siting plan. These plans are subject to Division review and revision.

(b) The minimum residential population of a community water system shall be determined by a mathematical calculation of the total number of active residential service connections multiplied be Georgia’s average population per household, as published in the most recent Federal Census Bureau Statistics. Multiple residential units served by a single connection (master meter) shall be included in the determination of population for a water system. The minimum monitoring frequency for total coliforms for community water systems is based on the population served by the system, as follows:

  Population                Minimum number of
    served                  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
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

(c) The monitoring frequency for total coliform for non-community water systems is as follows:

(d) The public water system must 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.

(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. Repeat samples are not considered special purpose samples, and must be used to determine compliance with the MCL for total coliforms.

(a) If a routine sample is total coliform-positive, the public water system must collect a set of repeat samples within 24 hours of being notified of the positive result. A system which collects more than one routine sample per month must collect no fewer than three repeat samples for each total coliform-positive sample found. A system which normally collects one routine sample per month or fewer must collect no fewer than four repeat samples for each total coliform-positive sample found. The Division may extend the 24-hour limit on a case- by-case basis if the system has a logistical problem in collecting the repeat samples within 24 hours that is beyond its control.

(b) The system must collect at least one repeat sample from the sampling tap where the original total coliform- positive sample was taken, and at least one repeat sample at a tap within five service connections upstream and at least one repeat sample at a tap within five service connections downstream of the original sampling site. If a total coliform-positive sample is at the end of the distribution system, or one away from the end of the distribution system, the Division may waive the requirement to collect at least one repeat sample upstream or downstream of the original sampling site.

(c) The system must collect all repeat samples on the same day, except that the Division may allow a system with a single service connection to collect the required set of repeat samples over a four-day period.

(d) If one or more repeat samples in the set is total coliform-positive, the public water system must collect an additional set of repeat samples in the manner specified in this section. The additional samples must be collected within 24 hours of being notified of the positive result, unless the Division extends the limit as provided in this section. The system must repeat this process until either total coliforms are not detected in one complete set of repeat samples or the system determines that the MCL for total coliforms has been exceeded and notifies the Division.

(e) If a system collecting fewer than five routine samples per month has one or more total coliform-positive samples and the Division does not invalidate the sample(s), it must collect at least five routine samples during the next month the system provides water to the public, except that the Division may waive this requirement if the conditions specified below are met. The Division cannot waive the requirement for a system to collect repeat samples.

(f) After a system collects a routine sample and before it learns the results of the analysis of that sample, if it collects another routine sample(s) from within five adjacent service connections of the initial sample, and the initial sample, after analysis, is found to contain total coliforms, then the system may count the subsequent sample(s) as a repeat sample instead of as a routine sample.

(g) Results of all routine and repeat samples not invalidated by the Division must be included in determining compliance with the MCL for total coliforms.

(a) The Division may invalidate a total coliform-positive sample only if the conditions that follow below are met.

(b) A laboratory must invalidate a total coliform sample (unless total coliforms are detected) if the sample produces a turbid culture in the absence of gas production using an analytical method where gas formation is examined (e.g., the Multiple-Tube Fermentation Technique), produces a turbid culture in the absence of an acid reaction in the Presence-Absence (P-A) Coliform Test, or exhibits confluent growth or produces colonies too numerous to count with an analytical method using a membrane filter (e.g., 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 24 hours of being notified of the interference problem, and have it analyzed for the presence of total coliforms. The system must continue to re-sample within 24 hours and have the samples analyzed until it obtains a valid result. The Division may waive the 24-hour time limit on a case-by-case basis.

(a) Public water systems which do not collect five or more routine samples per month must undergo an initial sanitary survey by June 29, 1994 for community public water systems and June 24, 1999 for non-community water systems. Thereafter, systems must undergo another sanitary survey every five years, except that non- community water systems using only protected and disinfected ground water, as defined by the Division, must undergo subsequent sanitary surveys at least every ten years after the initial sanitary survey.

(b) Sanitary surveys must be performed by the Division or an agent approved by the Division. The system is responsible for ensuring the survey takes place.

(a) If any routine or repeat sample is total coliform-positive, the system must analyze that total coliform-positive culture medium to determine if fecal coliforms are present, except that the system may test for E. coli in lieu of fecal coliforms. If fecal coliforms or E. coli are present, the system must notify the Division by the end of the day when the system is notified of the test result, unless the system is notified of the result after the Division office is closed, in which case the system must notify the Division before the end of the next business day.

(b) The Division has the discretion to allow a public water system, on a case-by-case basis, to forego fecal coliform or E. coli testing on a total coliform-positive sample if that system assumes that the total coliform- positive sample is fecal coliform-positive or E. coli-positive. Accordingly, the system must notify the Division as specified in this Section and the MCL applies.

(a) The standard sample volume required for total coliform analysis, regardless of analytical method used, is 100 ml.

(b) Public water systems need only determine the presence or absence of total coliforms; a determination of total coliform density is not required.

(c) Public water systems must conduct total coliform analyses in accordance with 40 CFR 141.21.

(d) Public water systems must conduct fecal coliform analyses in accordance with 40 CFR 141.21.

(a) A public water system which has exceeded the MCL for total coliforms must report the violation to the Division no later than the end of the next business day after it learns of the violation, and notify the public in accordance with this chapter.

(b) A public water system which has failed to comply with a coliform monitoring requirement, including the sanitary survey requirement, must report the monitoring violation to the Division within ten days after the system discovers the violation, and notify the public in accordance with this chapter.