Code of Maryland Regulations › Title 26 - DEPARTMENT OF ENVIRONMENT › Part 1 - SUBTITLES 01-07 › Subtitle 04 - REGULATION OF WATER SUPPLY, SEWAGE DISPOSAL, AND SOLID WASTE › Chapter 26.04.01 - Quality of Drinking Water in Maryland › Section 26.04.01.11-2 - Frequency of Repeat Sampling and Sample Invalidation for Total Coliform, and Triggered Source Water Monitoring

Current through Register Vol. 51, No. 14, July 12, 2024
A. Frequency of Repeat Sampling for Total
				  Coliform Until March 31, 2016.
(1) If a
				  routine sample is total coliform-positive, the supplier of water shall take
				  repeat samples within 24 hours from the time the system is notified of the
				  positive result. The Approving Authority may extend this time limit if the
				  system cannot collect the repeat samples within 24 hours. If the time limit is
				  extended, the Approving Authority shall specify how much time the system has to
				  collect the repeat samples. Systems with one service connection may follow the
				  alternative repeat monitoring as specified in §A(4) of this
				  regulation.
(2) The supplier of
				  water shall take the following number of repeat samples for each total
				  coliform-positive routine sample:
(a) Three
				  repeat samples when the supplier of water is required to collect more than one
				  routine sample a month; or
(b) Four
				  repeat samples when the supplier of water is required to collect one, or less
				  than one, routine sample a month.
(3) The supplier of water shall follow the
				  sampling method below, except the Approving Authority may determine an
				  alternative sampling plan if the conditions below cannot be met:
(a) Collect one repeat sample from the
				  original total coliform-positive tap; and
(b) Collect at least one other repeat sample
				  within five service connections upstream of the original site and another
				  within five service connections downstream of the original site.
(4) The supplier of water shall
				  collect all repeat samples on the same day, except systems with a single
				  service connection may collect check samples over a 4-day period or collect
				  larger sample volumes as long as the total sample volume equals:
(a) 400 milliliters, when the system is
				  required to take one, or less than one, routine sample a month; or
(b) 300 milliliters, when the system is
				  required to take more than one routine sample a month.
(5) If one or more repeat sample is total
				  coliform-positive, the supplier of water shall collect an additional set of
				  repeat samples in the manner specified in §A(1)-(4) of this regulation, until
				  one complete set of repeat samples contains no coliform, or the supplier of
				  water exceeds the maximum contamination level under Regulation .10 of this
				  chapter.
(6) A sample taken within
				  five service connections of a positive routine sample may be counted as a
				  repeat sample if the sample was collected after the positive routine sample but
				  before notification of the sample results.
(7) A supplier of water using a ground water
				  source subject to Regulation .05-5 of this chapter, shall perform triggered
				  source water monitoring in accordance with Regulation .11-2D-J of this chapter
				  if conditions described in Regulation .11-2D(1) of this chapter
				  exist.