Md. Code Regs. 26.04.01.11-2

Current through Register Vol. 51, No. 22, November 1, 2024

Section 26.04.01.11-2 - Frequency of Repeat Sampling and Sample Invalidation for Total Coliform, and Triggered Source Water Monitoring

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.

B. Repeat Sampling the Next Month Until March 31, 2016.

(1) When a supplier of water collects one or more total coliform-positive samples that are not invalidated under §C of this regulation, and is required to routinely take less than five routine samples a month, the supplier of water shall collect at least five routine samples the next month water is supplied to the public.

(2) Waiver.

(a) The Approving Authority may waive, in writing, the requirement in §B(1) of this regulation.

(b) The Approving Authority may only issue a waiver in accordance with §B(2)(c) or (d) of this regulation.

(c) The Approving Authority may issue a waiver if the Approving Authority performs a site visit before the end of the next month the system provides water to the public to determine whether additional sampling and corrective action is needed by the supplier of water.

(d) The Approving Authority may issue a waiver if the Approving Authority has determined why the sample was total coliform-positive and establishes that the supplier of water has corrected the problem before the end of the next sampling month. The supplier of water shall still collect at least one sample the next month the system supplies water to the public unless the Approving Authority determines that the system corrected the problem before the repeat samples were taken and all repeat samples were total coliform-negative. The Approving Authority may not waive the five-sample requirement solely on the grounds that the check samples were negative. The written waiver shall:

(i) Be signed by the supervisor of the State official recommending the waiver;

(ii) Include the specific cause of the positive result and the corrective action taken by the supplier of water; and

(iii) Be available to the EPA and the public.

C. Invalidation of Total Coliform Samples Until March 31, 2016.

(1) Invalidation by Approving Authority.

(a) The Approving Authority may invalidate a total coliform-positive sample when the conditions of §C(1)(b), (c), or (d) of this regulation have been met.

(b) The Approving Authority may invalidate a total coliform-positive sample when the laboratory establishes that improper sample analysis caused the positive result.

(c) The Approving Authority may invalidate a total coliform-positive sample when repeat samples collected as described in §A of this regulation demonstrate that the original total coliform-positive sample was caused by a domestic or another nondistribution system plumbing problem. This determination can only be made when all repeat samples taken at the original tap are total coliform-positive and all repeat samples collected within five service connections of the original tap are total coliform-negative. The Approving Authority may not invalidate a sample simply on the grounds that all repeat samples were negative.

(d) The Approving Authority may invalidate a total coliform-positive sample when the total coliform-positive sample result is caused by a condition which does not reflect the water quality of the distribution system. In this case, the decision to invalidate a positive coliform sample shall be in writing and signed by the supervisor of the official recommending the decision. The document shall include the specific cause of the total coliform-positive sample and action taken or to be taken by the supplier of water to correct the problem. This document shall be made available to the EPA and the public. The supplier of water shall still collect repeat samples as described in §A(1)-(4) of this regulation and use them to determine compliance with the maximum contaminant level.

(2) Invalidation by Laboratory.

(a) Unless total coliform is detected in a sample, a laboratory shall invalidate a sample if the sample:

(i) Produces a turbid culture in the absence of gas production using an analytic method when gas formation is examined;

(ii) Produces a turbid culture in the absence of an acid reaction in the presence-absence coliform test; or

(iii) Exhibits confluent growth or produces colonies too numerous to count with an analytical method using a membrane filter.

(b) When a laboratory invalidates a sample as described in §C(2)(a) of this regulation, the supplier of water shall collect another sample from the original location within 24 hours of notification of the invalidated sample. The supplier of water shall continue to resample until it obtains a valid result. The Approving Authority may waive the 24-hour limit on a case-by-case basis.

D. Triggered Source Water Monitoring for Ground Water Supplies.

(1) General Requirements Until March 31, 2016. A ground water supplier subject to Regulation .05-5 of this chapter shall conduct triggered source water monitoring pursuant to 40 CFR § 141.402(a) if the following conditions exist:

(a) The supplier does not provide at least 4-log treatment of viruses, using inactivation, removal, or a combination of 4-log virus inactivation and removal approved by the Approving Authority, before or at the first customer for each ground water source; and

(b) The supplier is notified that a sample collected under Regulation . 11A of this chapter is total coliform-positive and the sample is not invalidated under Regulation .11-2C of this chapter Until March 31, 2016.

(2) Sampling Requirements Until March 31, 2016. A groundwater supplier shall collect, within 24 hours of notification of the routine total coliform-positive sample, at least one ground water source sample from each ground water source in use at the time that the total coliform-positive sample was collected under Regulation .11 of this chapter until March 31, 2016,, except as provided in §D(2)(b) of this regulation.

(a) The Approving Authority may extend the 24-hour time limit on a case-by-case basis if the supplier cannot collect the ground water source water sample within 24 hours due to circumstances beyond its control. In the case of an extension, the Approving Authority must specify how much time the supplier has to collect the sample.

(b) If approved by the Approving Authority, suppliers with more than one ground water source may meet the requirements of §D(2) of this regulation by sampling a representative ground water source or sources. If directed by the Approving Authority, suppliers shall submit for approval a triggered source water monitoring plan. The plan shall include a sampling siting plan developed in accordance with Regulation .11A(5) of this chapter, and shall identify one or more ground water sources that are representative of each monitoring site in the supplier's sample siting plan until March 31, 2016, and that the supplier intends to use for representative sampling under §D(2) of this regulation.

(c) A ground water supplier serving 1,000 people or fewer may use a repeat sample collected from a ground water source to meet the requirements of §A of this regulation and to satisfy the monitoring requirements of §D(2) of this regulation for that ground water source. If the repeat sample collected from the ground water source is E. coli positive, the supplier shall comply with §D(3) of this regulation.

(3) Additional Requirements Until March 31, 2016. If the Approving Authority does not require corrective action under Regulation .05-5C of this chapter for a fecal indicator-positive source water sample collected under §D of this regulation that is not invalidated under §G of this regulation, the supplier shall collect five additional source water samples from the same source within 24 hours of being notified of the fecal indicator-positive sample.

(4) Consecutive and Wholesale Systems Until March 31, 2016.

(a) In addition to the other requirements of §D of this regulation, a consecutive ground water supplier that has a total coliform-positive sample collected under Regulation .11 of this chapter until March 31, 2016, shall notify the wholesale supplier or suppliers within 24 hours of being notified of the total coliform positive sample.

(b) In addition to the other requirements of §D of this regulation, a wholesale ground water supplier shall comply with the following:

(i) A wholesale ground water supplier that receives notice from a consecutive supplier it serves that a sample collected under Regulation .11 of this chapter until March 31, 2016, is total coliform positive shall, within 24 hours of being notified, collect a sample from its ground water source(s) under §D(2) of this regulation and analyze it for a fecal indicator under §F of this regulation.

(ii) If the sample collected under §D(4)(b)(i) of this regulation is fecal indicator-positive, the wholesale ground water supplier shall notify all consecutive suppliers served by that ground water source of the fecal indicator source water positive within 24 hours of being notified of the ground water source sample monitoring result and shall meet the requirements of this §D(3) of this regulation.

(5) Exceptions to the Triggered Source Water Monitoring Requirements Until March 31, 2016. A ground water supplier is not required to comply with the source water monitoring requirements of §D of this regulation if either of the following conditions exists:

(a) Until March 31, 2016, the Approving Authority determines, and documents in writing, that the total coliform-positive sample collected under Regulation . 11 of this chapter is caused by a distribution system deficiency; or

(b) Until March 31, 2016, the total coliform-positive sample collected under Regulation . 11 of this chapter, is collected at a distribution system location or under conditions that the Approving Authority determined -will cause total-coliform-positive samples,

(6) Beginning April 1, 2016, a groundwater supplier subject to Regulation .05-5 of this chapter shall conduct triggered source water monitoring pursuant to 40 CFR § 141.420(a) if the following conditions exist:

(a) The supplier does not provide at least 4-log treatment of viruses, using inactivation, removal, or a combination of 4-log virus inactivation and removal approved by the Approving Authority, before or at the first customer for each ground water source; and

(b) The supplier is notified that a sample collected under Regulations .11-4 D - G of this chapter is total coliform-positive and the sample is not invalidated under Regulation .11-4C(3) beginning April 1, 2016.

(7) Beginning April 1, 2016, a groundwater supplier shall collect, within 24 hours of notification of the routine total coliform-positive sample, at least one ground water source sample from each ground water source in use at the time that the total coliform-positive sample was collected under Regulations .11-4 D - G of this chapter beginning April 1, 2016, except as provided in §D(7)(b) of this regulation.

(a) The Approving Authority may extend the 24-hour time limit on a case-by-case basis if the supplier cannot collect the ground water source water sample within 24 hours due to circumstances beyond its control. In the case of an extension, the Approving Authority must specify how much time the supplier has to collect the sample.

(b) If approved by the Approving Authority, suppliers with more than one ground water source may meet the requirements of §D(7) of this regulation by sampling a representative ground water source or sources. If directed by the Approving Authority, suppliers shall submit for approval a triggered source water monitoring plan. The plan shall include a sampling siting plan developed in accordance with Regulation .11-4C of this chapter, and shall identify one or more ground water sources that are representative of each monitoring site in the supplier's sample siting plan developed in accordance with Regulation .11-4C of this chapter beginning April 1, 2016, and that the supplier intends to use for representative sampling under §D(7) of this regulation.

(c) Beginning April 1, 2016, a groundwater system serving 1,000 or fewer people may use a repeat sample collected from a ground water source to meet both the requirements of Regulation 11-4 of this chapter and to satisfy the monitoring requirements of paragraph §D(2) of this regulation for that ground water source only if the Approving Authority approves the use of E. coli as a fecal indicator for source water monitoring under §D of this regulation and approves the use of a single sample for meeting both the triggered source water monitoring requirements in §D of this regulation and the repeat monitoring requirements in Regulation .11-4H of this chapter. If the repeat sample collected from the ground water source is E. coli-positive, the system must comply with §D(3) of this regulation.

(8) Beginning April 1, 2016, if the Approving Authority does not require corrective action under Regulation .05-5C of this chapter for a fecal indicator-positive source water sample collected under §D of this regulation that is not invalidated under §G of this regulation, the supplier shall collect five additional source water samples from the same source within 24 hours of being notified of the fecal indicator-positive sample.

(9) Consecutive and Wholesale Systems beginning April 1, 2016.

(a) In addition to the other requirements of §D of this regulation beginning April 1, 2016, a consecutive ground water supplier that has a total coliform-positive sample collected under Regulations .11-4 D - G of this chapter shall notify the wholesale supplier or suppliers within 24 hours of being notified of the total coliform positive sample.

(b) In addition to the other requirements of §D of this regulation, a wholesale ground water supplier shall comply with the following:

(i) Beginning April 1, 2016, a wholesale ground water supplier that receives notice from a consecutive supplier it serves that a sample collected under Regulations .11-4D - G of this chapter is total coliform positive shall, within 24 hours of being notified, collect a sample from its ground water source(s) in accordance with §D(7) of this regulation and analyze it for a fecal indicator in accordance with §F of this regulation.

(ii) If the sample collected under §D(4)(b)(i) of this regulation is fecal indicator-positive, the wholesale ground water supplier shall notify all consecutive suppliers served by that ground water source of the fecal indicator source water positive result within 24 hours of being notified of the ground water source sample monitoring result and shall meet the requirements of §D(3) of this regulation.

(10) Beginning April 1, 2016, a ground water supplier is not required to comply with the source water monitoring requirements of §D of this regulation if either of the following conditions exists:

(a) The Approving Authority determines, and documents in writing, that the total coliform-positive sample collected under Regulations .11-4 D - G of this chapter beginning April 1, 2016 is caused by a distribution system deficiency; or

(b) The total coliform-positive sample collected under Regulations .11-4 D - G of this chapter beginning April 1, 2016 is collected at a distribution system location or under conditions that the Approving Authority determined will cause total-coliform-positive samples.

E. Assessment Source Water Monitoring. If directed by the Approving Authority, ground water suppliers shall conduct assessment source water monitoring. A ground water supplier conducting assessment source water monitoring may use a triggered source water sample collected under §D(1) of this regulation to meet the assessment source water monitoring. If assessment source water monitoring is required by the Approving Authority, the monitoring shall include:

(1) Collection of a total of 12 ground water source samples that represent each month the supplier provides ground water to the public;

(2) Collection of samples from each well unless the supplier obtains written approval from the Approving Authority to conduct monitoring at one or more wells within the ground water system that are representative of multiple wells used by that supplier and that draw water from the same hydrogeologic setting;

(3) Collection of a standard sample volume of at least 100 mL for fecal indicator analysis regardless of the fecal indicator or analytical method used;

(4) Analysis of all ground water source samples using one of the analytical methods listed in 40 CFR § 141.402(c)(2) for the presence of E. coli;

(5) Collection of ground water source samples at a location prior to any treatment of the ground water source unless the Approving Authority approves a sampling location after treatment; and

(6) Collection of ground water source samples at the well itself unless the system's configuration does not allow for sampling at the well itself and the Approving Authority approves an alternate sampling location that is representative of the water quality of that well.

F. Analytical Methods.

(1) A ground water supplier subject to the source water monitoring requirements of §D of this regulation shall collect a standard sample volume of at least 100 mL for fecal indicator analysis regardless of the fecal indicator or analytical method used.

(2) A ground water supplier shall analyze all ground water source samples collected under §D of this regulation using one of the analytical methods listed in the table in 40 CFR § 141.402(c)(2) for the presence of E. coli, enterococci, or coliphage.

G. Invalidation of a Fecal Indicator Positive Ground Water Source Sample.

(1) A ground water supplier may obtain invalidation from the Approving Authority for a fecal indicator-positive ground water source sample collected under §D of this regulation only under the following conditions:

(a) The supplier provides the Approving Authority with written notice from the laboratory that improper sample analysis occurred; or

(b) The Approving Authority determines and documents in writing that there is substantial evidence that a fecal indicator-positive ground water source sample is not related to source water quality.

(2) If the Approving Authority invalidates a fecal indicator-positive ground water source sample, the ground water supplier shall collect another source water sample under §D of this regulation within 24 hours of being notified by the Approving Authority of its invalidation decision and shall have it analyzed for the same fecal indicator using the analytical methods in §F of this regulation. The Approving Authority may extend the 24-hour time limit on a case-by-case basis if the supplier cannot collect the source water sample within 24 hours due to circumstances beyond its control. In the case of an extension, the Approving Authority shall specify how much time the supplier has to collect the sample.

H. Sampling location.

(1) Any ground water source sample required under §D of this regulation shall be collected at a location prior to any treatment of the ground water source unless the Approving Authority approves a sampling location after treatment.

(2) If the system's configuration does not allow for sampling at the well itself, the supplier may collect a sample at a location approved by the Approving Authority to meet the requirements of §D of this regulation if the sample is representative of the water quality of that well.

I. New Sources. If directed by the Approving Authority, a ground water supplier that places a new ground water source into service after November 30, 2009, shall conduct assessment source water monitoring under §E of this regulation. If directed by the Approving Authority, the supplier shall begin monitoring before the ground water source is used to provide water to the public.

J. Public Notification.

(1) A ground water supplier with a ground water source sample collected under §D or E of this regulation that is fecal indicator-positive and that is not invalidated under §G of this regulation, including consecutive suppliers served by the ground water source, shall conduct public notification under Regulation .20B of this chapter.

(2) Monitoring Violations. Failure to meet the requirements of §§D-I of this regulation is a monitoring violation and requires the ground water supplier to provide public notification under Regulation .20D of this chapter.

Md. Code Regs. 26.04.01.11-2

Regulation .11-2 adopted effective December 21, 1992 (19:25 Md. R. 2208); amended effective 43:17 Md. R. 957, eff. 8/29/2016