Michigan Administrative Code › Department - Environmental Quality › Drinking Water And Municipal Assistance Division › Supplying Water to the Public › Part 7 - SURVEILLANCE, INSPECTION, AND MONITORING › Section R. 325.10704c - Total coliform; general monitoring

Current through Vol. 24-12, July 15, 2024
Rule 704c.
(1)
				  Sample siting plan requirements for compliance with the total coliform rules in
				  R 325.10704a are all of the following:
(a)
				  Supplies shall develop a written sample siting plan that identifies sampling
				  sites and a sample collection schedule that are representative of water
				  throughout the distribution system not later than March 31, 2016. These plans
				  are subject to department review and revision. Supplies shall collect total
				  coliform samples according to the written sample siting plan. Monitoring
				  required by R 325.10704d to R 325.10704h may take place at a customers premise,
				  dedicated sampling station, or other designated compliance sampling location.
				  Routine and repeat sample sites and the sampling points necessary to meet the
				  requirements of the groundwater rules of
				  R 325.10739 to
				  R 325.10739b shall be reflected in
				  the sampling plan.
(b) Supplies
				  shall collect samples at regular time intervals throughout the month, except
				  that supplies that use only ground water and serve 4,900 or fewer people may
				  collect all required samples on a single day if they are taken from different
				  sites.
(c) Supplies shall take at
				  least the minimum number of required samples even if the supply has had an E.
				  coli MCL violation or has exceeded the coliform treatment technique triggers in
				  R 325.10704i(1).
(d) A supply may
				  conduct more compliance monitoring than is required by these total coliform
				  rules R 325.10704a to R 325.10704k to investigate potential problems in the
				  distribution system and use monitoring as a tool to assist in uncovering
				  problems. A supply may take more than the minimum number of required routine
				  samples and shall include the results in calculating whether the coliform
				  treatment technique trigger in R 325.10704i(1)(a)(i) and (ii) has been exceeded
				  only if the samples are taken in accordance with the existing sample siting
				  plan and are representative of water throughout the distribution
				  system.
(e) Supplies shall identify
				  repeat monitoring locations in the sample siting plan. All of the following
				  apply to repeat monitoring locations:
(i)
				  Unless the provisions of paragraph (iii) of this subdivision are met, the
				  supply shall collect at least 1 repeat sample from the sampling tap where the
				  original total coliform-positive sample was taken, and at least 1 repeat sample
				  at a tap within 5 service connections upstream and at least 1 repeat sample at
				  a tap within 5 service connections downstream of the original sampling site. If
				  a total coliform-positive sample is at the end of the distribution system, or 1
				  service connection away from the end of the distribution system, the supply
				  shall still take all required repeat samples. However, the department may allow
				  an alternative sampling location instead of the requirement to collect at least
				  1 repeat sample upstream or downstream of the original sampling site.
(ii) Supplies required to conduct triggered
				  source water monitoring under
				  R 325.10739(1)(a)
				  shall take ground water source sample or samples in addition to repeat samples
				  required under these total coliform rules R 325.10704a to R
				  325.10704k.
(iii) Supplies may
				  propose repeat monitoring locations to the department that the supply believes
				  to be representative of a pathway for contamination of the distribution system.
				  A supply may elect to specify either alternative fixed locations or criteria
				  for selecting repeat sampling sites on a situational basis in a standard
				  operating procedure (SOP) in its sample siting plan. The supply shall design
				  its SOP to focus the repeat samples at locations that best verify and determine
				  the extent of potential contamination of the distribution system area based on
				  specific situations. The department may modify the SOP or require alternative
				  monitoring locations as needed.
(f) The department may review, revise, and
				  approve, as appropriate, repeat sampling proposed by supplies under subdivision
				  (e)(iii) of this subrule. The supply shall demonstrate that the sample siting
				  plan remains representative of the water quality in the distribution system.
				  The department may determine that monitoring at the entry point to the
				  distribution system (especially for undisinfected ground water supplies) is
				  effective to differentiate between potential source water and distribution
				  system problems.