Microbiological sampling and monitoring requirements

1. Monitoring requirements. a. General. The provisions set forth under title 40 Code of Federal Regulations part 141, subpart Y, include both the maximum contaminant level and treatment technique requirements for all public water systems. b. Sample siting plans. All total coliform samples must be collected according to a written sample siting plan. Systems must develop a written sample siting plan that identifies the sample collection schedule and sampling sites that are representative of the water throughout the distribution system. This plan must be submitted to the department. The plan is subject to department review and revisions. Routine, repeat, and any sampling sites necessary to meet the requirements specified under title 40 Code of Federal Regulations part 141, subparts S and Y must be shown on the plan. (1) The routine samples must be collected at regular time intervals throughout the month except that systems using ground water and serving four thousand nine hundred people or less may collect all of the required samples on a single day if the samples are collected from different sites. (2) Systems must take at least the minimum number of required samples even if the system has had an E. coli maximum contaminant level violation or has exceeded the coliform treatment technique triggers as specified in title 40 Code of Federal Regulations part 141, subpart Y. (3) Systems may take more than the minimum number of required routine samples and these results must be used to determine whether a coliform treatment technique trigger has been exceeded as specified in title 40 Code of Federal Regulations part 141, subpart Y. All routine and repeat total coliform samples must be taken in accordance with the existing sample siting plan. (4) Repeat monitoring locations must be identified in the sample siting plan. The repeat samples must be collected at the following locations, unless the provisions of paragraphs (b)(5)(a) or (b)(5)(b) are met: (a) At least one repeat sample must be collected from the original sampling site that was total coliform-positive. (b) At least one repeat sample must be collected from a site within five service connections upstream of the original total coliform-positive sampling site. (c) At least one repeat sample must be collected from a site within five service connections downstream of the original total coliform-positive sampling site. (5) If the original total coliform-positive sampling site is at or one away from the end of the distribution system the department may waive the requirement to collect at least one repeat sample upstream or downstream of the original total coliform-positive sampling site. The system must still take all required repeat samples. However, the department may allow alternate sampling locations other than the upstream or downstream sites. Systems required to conduct triggered source water monitoring as set forth under title 40 Code of Federal Regulations part 141, subpart S, must take ground water source samples in addition to the required repeat sampling. (a) Systems may elect to identify alternative fixed repeat locations or criteria for selecting repeat sampling sites on a case-by-case basis in a standard operating procedure. These repeat monitoring locations should be indicative of a pathway for contamination of the distribution system. The department shall review the alternative repeat monitoring locations to verify and determine the extent of potential contamination of the distribution system at the specific alternative repeat monitoring location. The department shall review the alternative repeat monitoring locations as needed. (b) Ground water systems which serve one thousand or fewer persons may propose repeat sampling locations that differentiate potential source water and distribution system contamination, such as by sampling at entry points to the distribution system. A ground water system with a single well required to conduct triggered source water monitoring may, with the approval of the department, take one of its repeat samples at the triggered source water monitoring location as set forth under title 40 Code of Federal Regulations part 141.402(a), subpart S. The system must demonstrate, to the department's satisfaction, the sample siting plan remains representative of water quality in the distribution system. If approved by the department, the system may use that sample result to meet the monitoring requirements as set forth under title 40 Code of Federal Regulations part 141.402(a), subpart S and under title 40 Code of Federal Regulations part 141.853(a)(5)(ii), subpart Y. [1] If a repeat sample is taken at a triggered source water monitoring location and is positive for E. coli bacteria, the system has violated the E. coli maximum contaminant level and must also comply with title 40 Code of Federal Regulations part 141.402(a)(3), subpart S. If a system takes more than one repeat sample at the triggered source water monitoring location, the system may reduce the number of additional source water samples required under title 40 Code of Federal Regulations part 141.402(a)(3), subpart S by the number of repeat samples taken at that location that were not positive for E. coli bacteria. [2] If more than one repeat sample is taken at a triggered source water monitoring location under title 40 Code of Federal Regulations part 141.402(a), subpart S and more than one repeat sample is positive for E. coli bacteria, the system has violated the E. coli maximum contaminant level and must also comply with title 40 Code of Federal Regulations part 141.403(a)(1), subpart S. [3] If all repeat samples taken at a triggered source water monitoring location are E. coli-negative and a repeat sample that is taken at a monitoring location other than the triggered source water monitoring location is E. coli-positive, the system has violated the E. coli maximum contaminant level, but is not required to comply with title 40 Code of Federal Regulations part 141.402(a)(3), subpart S. (6) Any alternative repeat monitoring locations or triggered source water monitoring locations as specified under title 40 Code of Federal Regulations part 141, subpart Y and under title 40 Code of Federal Regulations part 141, subpart S, will be reviewed and approved by the department. When using these sites, the system must demonstrate that the sample siting plan remains representative of the water quality in the distribution system. It may be determined that monitoring at the entry point to the distribution system, such as for undisinfected ground water systems, is an effective way to differentiate between potential source water and distribution system problems. c. Special purpose samples. Special purpose samples, such as those taken to determine whether disinfection practices following pipe placement, replacement, or repair are sufficient, and samples invalidated by the department or laboratory, must not be used to determine whether the coliform treatment technique trigger has been exceeded as specified under title 40 Code of Federal Regulations part 141, subpart Y. Repeat samples taken in accordance with title 40 Code of Federal Regulations part 141, subpart Y are not considered special purpose samples and must be used to determine whether the coliform treatment technique trigger has been exceeded. d. Invalidation of total coliform samples. Any total coliform-positive samples invalidated under title 40 Code of Federal Regulations part 141, subpart Y, do not count towards meeting the minimum monitoring requirements. The department may invalidate a total coliform-positive sample only if one of the following conditions is met: (1) The laboratory establishes the total coliform-positive result was caused by improper sample analysis. (2) The department determines, based upon the results of the repeat samples as required under title 40 Code of Federal Regulations part 141, subpart Y, that the total coliform-positive sample resulted from a domestic or other nondistribution system problem. This provision applies only to systems that have more than one service connection and only if: (a) All repeat samples collected at the same site as the original total coliform-positive sample are also total coliform-positive; and (b) All repeat samples collected at a location other than the original total coliform-positive sample site are total coliform-negative. (3) The department may determine that substantial grounds exist to indicate that the total coliform-positive result was due to a circumstance or condition not reflective of the water quality in the distribution system. The system must still collect all repeat samples and use them to determine whether a coliform treatment technique trigger has been exceeded as specified under title 40 Code of Federal Regulations part 141, subpart Y. To invalidate a total coliform-positive sample under this provision, the decision and supporting paperwork must be documented in writing and approved and signed by the supervisor of the state official who recommended the decision. The department shall make this document available to the environmental protection agency and to the public. The written documentation must state the specific cause of the total coliform-positive sample and what action the system has or will take to correct the problem. Invalidation may not be based soley on the grounds that all repeat samples are total coliform-negative. A laboratory must invalidate a total coliform sample, unless total coliforms are detected, only if one of the following conditions is met: (1) The sample produces a turbid culture in the absence of gas production using an analytical technique where gas formation is examined, such as the multiple-tube fermentation technique; (2) The sample produces a turbid culture in the absence of an acid reaction in the presence-absence coliform test; or (3) The sample exhibits confluent growth or produces colonies too numerous to count with an analytical technique using a membrane filter, such as membrane filter technique. Systems must collect a replacement sample for total coliform bacteria analysis from the same location as the original sample if the original sample is invalidated by the department or laboratory. Replacement samples must be collected within twenty-four hours of notification by the department or laboratory and submitted for total coliform analysis. The system must continue to resample within twenty-four hours and have the sample analyzed for total coliforms until a valid result is obtained. The department may waive the twenty-four hour time limit on a case-by-case basis. Criteria the department may implement for waiving the twenty-four hour sampling time frame includes the following: (1) Laboratory closures; or (2) Mail delivery issues. 2. Monitoring frequency. a. General. All public water systems shall sample for total coliform bacteria in each calendar month that the system provides water to the public. The number of samples required must be determined by the population served by the system. The population range of twenty-five to one thousand includes public water systems which have at least fifteen service connections, but that serve less than twenty-five persons. POPULATION SERVED MINIMUM NUMBER 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 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 Following any total coliform-positive sample taken, systems must comply with the repeat monitoring requirements and E. coli analytical requirements as specified in title 40 Code of Federal Regulations part 141, subpart Y. As set forth under title 40 Code of Federal Regulations part 141, subpart Y, once all routine and repeat monitoring for a calendar month has been completed, either the system or the department must determine whether any coliform treatment technique triggers have been exceeded. The system must complete any assessments associated to the triggers. b. Seasonal noncommunity water systems. All seasonal noncommunity water systems, including systems that keep the distribution system pressurized year-round must complete a state-approved start-up procedure. Start-up procedures may include source and distribution system disinfection and collection and analysis of water samples for total coliform bacteria. The system must certify back to the department, within fourteen days of opening, the start-up procedure was completed. c. Unfiltered subpart H systems. At the discretion of the department, systems that use surface water or ground water under the direct influence of surface water that do not filter in compliance with title 40 Code of Federal Regulations part 141, subparts H, P, T, and W must collect at least one sample for total coliform bacteria analysis near the first service connection each day that the turbidity level of the source water exceeds one nephelometric turbidity unit as specified in title 40 Code of Federal Regulations part 141, subpart H. The sample must be collected within twenty-four hours of the first exceedance unless the department determines that the system, due to logistical or other problems beyond its control, cannot have the sample analyzed within thirty hours of collection. The system must identify an alternative sample collection schedule. The sample result must be included in determining whether the coliform treatment technique trigger has been exceeded as specified under title 40 Code of Federal Regulations part 141, subpart Y. 3. Repeat monitoring and E. coli requirements. a. Repeat monitoring. If a routine sample collected under the requirements specified in title 40 Code of Federal Regulations part 141, subpart Y is total coliform-positive, a system must collect no fewer than a set of three repeat samples for total coliform bacteria analysis for each total coliform-positive routine sample. The system must collect the set of repeat samples within twenty-four hours of being notified by the department or the laboratory of the positive total coliform sample. The department may extend the twenty-four hour time limit on a case-by-case basis if the system has a logistical problem or other problems beyond the system's control. The department may choose criteria for the system to use in lieu of the case-by-case decisions. The department shall specify to the system the time frame for collecting the repeat samples. The department may not waive the requirement to collect repeat samples under these provisions. All repeat samples must be collected on the same day except that the department may allow systems with a single service connection to: (1) Collect the required set of repeat samples over a three-day period; or (2) Collect a larger volume repeat sample in one or more sample containers of any size as long as the total volume collected is at least three hundred milliliters. If one or more repeat samples in the set of required repeat samples is total coliform-positive, an additional set of repeat samples must be collected, within twenty-four hours unless the department extends the twenty-four hour time frame, meeting the requirements set forth under title 40 Code of Federal Regulations part 141, subpart Y. Additional sets of repeat samples must be collected until no total coliform bacteria are detected in one complete set or the department determines a coliform treatment technique trigger as specified in title 40 Code of Federal Regulations part 141, subpart Y, has been exceeded as a result of a repeat sample being total coliform-positive. If a coliform treatment technique trigger, as identified in this provision, has been exceeded as a result of a routine sample being total coliform-positive, the system only needs to conduct one round of repeat monitoring for each total coliform-positive routine sample. The system shall report to the department and notify the public when an E. coli maximum contaminant level is exceeded. After a system collects a routine sample and before it learns the results of that sample, if the system collects another routine sample from within five adjacent service connections of the first sample, and the first sample, after analysis, is found to contain total coliform bacteria, the system may count the subsequent sample as a repeat sample instead of a routine sample. All routine and repeat results taken under title 40 Code of Federal Regulations part 141, subpart Y, and not invalidated by the department or laboratory, must be used to determine whether a coliform treatment technique trigger, under the provision stated above, has been exceeded. b. E. coli testing. A system must analyze each total coliform-positive routine or repeat sample for E. coli bacteria. The system must notify the department by the end of the business day or by the end of the next business day if the department offices are closed of a positive E. coli bacteria result. The department or laboratory will not forgo E. coli testing on any total coliform-positive bacteria sample. 4. Assessment requirements. a. Level 1 assessment. A level 1 assessment must be performed as soon as possible when a system exceeds a level 1 treatment technique trigger as specified in title 40 Code of Federal Regulations part 141, subpart Y. A level 1 assessment must be conducted by the water system operator or by a consultation, such as a phone interview or onsite visit, with the department. When completing the level 1 assessment, the system must describe sanitary defects found, what corrective actions were completed, the proposed time frame for any remaining corrective actions that need to be addressed, and any other department directives that may be required. The system may note on the assessment form that no sanitary defects were identified. Within thirty days after learning of a treatment technique trigger exceedance, the system must submit a completed level 1 assessment form to the department. The department may extend the thirty-day time frame on a case-by-case basis. The department shall review the completed level 1 assessment and determine if the assessment is sufficient. The assessment form must include proposed time frames for any corrective actions not completed. If the department determines the level 1 assessment not to be sufficient, the department shall consult with the system. If the department requires any revisions to the level 1 assessment, the system must submit, to the department, a revised level 1 assessment form on an agreed-upon schedule that will not exceed thirty days from the date of the consultation. The department shall review the completed assessment form and determine if the cause of the level 1 assessment was found. If the cause of the level 1 assessment was found, the system must describe how the problem was corrected. The department shall determine on a case-by-case basis the schedule for any corrective actions that need to be addressed. b. Level 2 assessment. A level 2 assessment must be performed as soon as possible when a system exceeds a level 2 treatment technique trigger as specified in title 40 Code of Federal Regulations part 141, subpart Y. The system must comply with any expedited actions or additional actions required by the department in the case of an E. coli maximum contaminant level violation. The department shall require a level 2 assessment be completed before a boil water order is lifted. Only the department may perform a level 2 assessment as a result of an E. coli maximum contaminant level violation. A level 2 assessment will be conducted by the department or department-approved assessors. A system may conduct a level 2 assessment if the system has personnel with the certification or qualifications as specified by the department. A system must have personnel with an operator certification level one level higher than the water system being evaluated. When completing the level 2 assessment, the system must describe sanitary defects found, what corrective actions were completed, the proposed time frame for any remaining corrective actions that need to be addressed, and any other department directives that may be required. The system may note on the assessment form that no sanitary defects were identified. Within thirty days after learning of a treatment technique trigger exceedance, the system must submit a completed level 2 assessment form to the department. The department may extend the thirty-day time frame on a case-by-case basis. The department shall review the completed level 2 assessment and determine if the assessment is sufficient. The assessment form must include proposed time frames for any corrective actions not completed. If the department determines the level 2 assessment not to be sufficient, the department shall consult with the system. If the department requires any revisions to the level 2 assessment, the system must submit, to the department, a revised level 2 assessment form on an agreed-upon schedule that does not exceed thirty days from the date of the consultation. The department shall review the completed assessment form and determine if the cause of the level 2 assessment was found. If the cause of the level 2 assessment was found, the system must describe how the problem was corrected. The department shall determine on a case-by-case basis the schedule for any corrective actions that need to be addressed. c. Corrective actions. A system must correct any sanitary defects identified in either the level 1 or the level 2 assessment as specified under title 40 Code of Federal Regulations part 141, subpart Y. If any corrective actions cannot be corrected by the time the level 1 or the level 2 assessment form is required to be submitted to the department, the system must complete the corrective action(s) in accordance with an approved time frame decided upon during the consultation between the system and the department. The system must notify the department when each corrective action is completed. d. Consultation. The department or the system may at any time during the assessment or corrective action phase request a consultation with the other entity to determine the appropriate actions that need to be taken. The system may consult with the department on all relevant information that may affect its ability to complete the corrective action, a proposed time frame scheduled for a corrective action, or any other department directives. 5. Sanitary surveys. a. Frequency. All surface water and ground water under the direct influence of surface water systems shall undergo a sanitary survey no less frequently than once every year. All systems purchasing surface water or ground water under the direct influence of surface water shall undergo a sanitary survey no less frequently than once every three years. Community ground water systems, including systems purchasing ground water, that are not providing at least four-log treatment of viruses and have not been determined by the department to exhibit outstanding performance shall undergo a sanitary survey no less frequently than once every three years. Community ground water systems, including systems purchasing ground water, which are providing at least four-log treatment of viruses or which have been determined by the department to exhibit outstanding performance shall undergo a sanitary survey no less frequently than once every five years. Noncommunity ground water systems, including systems purchasing ground water, which are not providing at least four-log treatment of viruses shall undergo a sanitary survey no less frequently than once every three years. Noncommunity ground water systems, including systems purchasing ground water, that are providing at least four-log treatment of viruses shall undergo a sanitary survey no less frequent than once every five years. The department will allow sanitary surveys to be phased. The components of the phased sanitary survey must be completed within the established frequency. b. Responsibilities. Sanitary surveys must be performed by the department or an agent approved by the department. Information collected on sources of contamination within a delineated wellhead protection area during the development and implementation of an approved wellhead protection program, if available, must be considered when conducting sanitary surveys. The department shall review the sanitary surveys for systems serving one thousand persons or less to determine if the system is taking the proper number of monthly total coliform bacteria samples. Public water systems are responsible for ensuring that the required sanitary surveys are conducted.