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. 325.10719e - Disinfectant residuals, disinfection byproducts, and disinfection byproduct precursors; monitoring requirements

Current through Vol. 24-12, July 15, 2024
Rule 719e.
(1)
				  This rule applies as set forth in
				  R 325.10610b. All of the following
				  provisions are general monitoring requirements:
(a) Supplies shall take all samples during
				  normal operating conditions.
(b)
				  Supplies may consider multiple wells drawing water from a single aquifer as 1
				  treatment plant for determining the minimum number of TTHM and HAA5 samples
				  required, with department approval. This approval will be granted in writing if
				  the supply can demonstrate that the finished water quality characteristic of
				  all entry points to the distribution system drawing from the identified
				  aquifer, whether served by multiple wells or a single well, are similar and are
				  expected to react alike in terms of the formation of disinfection byproducts.
				  To demonstrate this, the supply shall arrange for a study to be prepared by an
				  individual or firm considered qualified to perform this work, such as a
				  hydrogeologist, geologist, or engineer. All of the following provisions apply
				  to the study:
(i) The study shall consider
				  well construction and geology, including all of the following:
(A) Well locations marked on a topographical
				  map.
(B) Well depths.
(C) Well logs showing geological strata,
				  identifying water production zones, screened or slotted areas, and grouting of
				  the annular space.
(D) Static water
				  levels.
(E) Aquifer studies and
				  maps.
(F) Treatment
				  applied.
(ii) The study
				  shall consider water characteristics and chemistry of each well including all
				  of the following:
(A) Field pH.
(B) Field temperatures.
(C) Specific conductivity.
(D) Total organic carbon.
(E) Analyses of common ions with a calculated
				  cation/ion balance, such as calcium, magnesium, iron, manganese, sodium
				  sulfate, alkalinity, and chloride.
(iii) The department may require disinfection
				  byproducts monitoring at various entry points to the distribution system to
				  determine if the study conclusions are correct.
(iv) Results of disinfection byproducts
				  monitoring may be used instead of the study if all entry points to the
				  distribution system drawing from the identified aquifer show that the levels
				  are below the MCLs.
(c)
				  Failure to monitor in accordance with the monitoring plan required under
				  subrule (5) of this rule is a monitoring violation.
(d) Failure to monitor will be treated as a
				  violation for the entire period covered by the annual average where compliance
				  is based on a running annual average of monthly or quarterly samples or
				  averages and the supply's failure to monitor makes it impossible to determine
				  compliance with MCLs or MRDLs.
(e)
				  Supplies shall use only data collected under this rule to qualify for reduced
				  monitoring.