1. A. Applicability. All public water suppliers that use ground water are subject to the requirements of 40 CFR §141 Subpart S except public water suppliers that combine all of their ground water with surface water or with ground water under the direct influence of surface water prior to treatment under 40 CFR §141 Subpart H. For the purposes of this regulation, "ground water system” is defined as any public water system subject to 40 CFR §141 Subpart S, including consecutive systems receiving finished ground water.

2. B. General Requirements. Ground water suppliers subject to 40 CFR §141 Subpart S shall comply with the following requirements:

   1. (1) Sanitary survey information requirements for all ground water systems in accordance with Regulation .11-3D of this chapter.
   2. (2) Microbial source water monitoring requirements for ground water suppliers that do not treat all of their ground water to at least 99.99 percent (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 in accordance with Regulation .11-2 of this chapter.

   3. (3) Treatment technique requirements, described in 40 CFR §141.403, that apply to ground water systems that have fecally contaminated source waters, as determined by source water monitoring conducted under 40 CFR §141.402, or that have significant deficiencies that are identified by the Approving Authority, or that are identified by EPA under the Safe Drinking Water Act section 1445. A ground water supplier with fecally contaminated source water or with significant deficiencies subject to the treatment technique requirements of 40 CFR §141 Subpart S shall implement one or more of the following corrective action options:

      1. (a) Correct all significant deficiencies;
      2. (b) Provide an alternate source of water;
      3. (c) Eliminate the source of contamination; or
      4. (d) Provide treatment that reliably achieves 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.
   4. (4) Ground water suppliers that 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 are required to conduct compliance monitoring to demonstrate treatment effectiveness, as described in Regulation .11D of this chapter.
   5. (5) If requested by the Approving Authority, ground water suppliers shall provide the Approving Authority with any existing information that will enable the Approving Authority to perform a hydrogeologic sensitivity assessment. For the purpose of this regulation, “hydrogeologic sensitivity assessment” means a determination of whether groundwater suppliers obtain water from hydrogeologically sensitive settings.

3. C. Ground Water Suppliers with Significant Deficiencies Or Source Water Fecal Contamination.

   1. (1) When a significant deficiency, such as an aspect of the system that may have potential to cause risks to public health, is identified by the Approving Authority, or when a ground water source sample collected under Regulation .11-2D of this chapter is fecal indicator-positive or as otherwise specified in this regulation, the ground water suppliers shall meet the treatment technique requirements of 40 CFR §141.403.
   2. (2) If directed by the Approving Authority, a ground water supplier with a ground water source sample collected under Regulation .11-2D(2), D(4) or E of this chapter that is fecal indicator-positive shall comply with the treatment technique requirements of §C of this regulation.
   3. (3) When a significant deficiency is identified by the Approving Authority at a Subpart H public water supplier that uses both ground water and surface water, the supplier shall comply with provisions of §C of this regulation except in cases where the Approving Authority determines that the significant deficiency is in a portion of the distribution system that is served solely by surface water or ground water under the direct influence of surface water.
   4. (4) Unless the Approving Authority directs the ground water supplier to implement a specific corrective action, the ground water supplier shall consult with the Approving Authority regarding the appropriate corrective action within 30 days of receiving written notice from the Approving Authority of a significant deficiency, written notice from a laboratory that a ground water source sample collected under Regulation .11-2D(3) of this chapter was found to be fecal indicator-positive, or direction from the Approving Authority that a fecal indicator-positive collected under Regulation .11-2D(2) or (4) or E of this chapter requires corrective action. For the purposes of 40 CFR §141 Subpart S, significant deficiencies include, but are not limited to, defects in design, operation, or maintenance, or a failure or malfunction of the sources, treatment, storage, or distribution system that the Approving Authority determines to be causing, or have potential for causing, the introduction of contamination into the water delivered to consumers.

   5. (5) Within 120 days (or earlier if directed by the Approving Authority) of receiving written notification from the Approving Authority of a significant deficiency, written notice from a laboratory that a ground water source sample collected under Regulation .11-2D(3) of this chapter was found to be fecal indicator-positive, or direction from the Approving Authority that a fecal indicator-positive sample collected under Regulation .11-2D(2) or (4) or E of this chapter requires corrective action, the ground water supplier shall either:

      1. (a) Have completed corrective action in accordance with applicable Approving Authority plan review processes or other Approving Authority guidance or direction, if any, including Approving Authority-specified interim measures; or

      2. (b) Be in compliance with an approved corrective action plan and schedule subject to the following conditions:

         1. (i) Any subsequent modifications to an approved corrective action plan and schedule must also be approved by the Approving Authority; and
         2. (ii) If the Approving Authority specifies interim measures for protection of the public health pending approval of the corrective action plan and schedule, or pending completion of the corrective action plan, the supplier shall comply with these interim measures as well as with any schedule specified by the Approving Authority.

   6. (6) Corrective Action Alternatives. Ground water suppliers that meet the conditions of §C(1) or (2) of this regulation shall implement one or more of the following corrective action alternatives:

      1. (a) Correct all significant deficiencies;
      2. (b) Provide an alternate source of water;
      3. (c) Eliminate the source of contamination; or
      4. (d) Provide treatment that reliably achieves 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 the ground water source.

   7. (7) Special Notice to the Public of Significant Deficiencies or Source Water Fecal Contamination.

      1. (a) For ground water suppliers required to comply with 40 CFR §141 Subpart S, any supplier that receives notice from the Approving Authority of a significant deficiency, or notice from a laboratory of a fecal indicator-positive ground water source sample that is not invalidated by the Approving Authority under Regulation .11-2G of this chapter, shall comply with special public notice requirements of 40 CFR §141.153(h)(6) and Regulation .20B(3) of this chapter.
      2. (b) In addition to the applicable public notice requirements of 40 CFR §141.202, community ground water suppliers shall comply with special public notification requirements set forth in Regulation .20B(3) of this chapter.

4. D. Treatment technique violations for ground water suppliers.

   1. (1) A ground water supplier with a significant deficiency is in violation of the treatment technique requirement if, within 120 days (or earlier if directed by the Approving Authority) of receiving written notice from the Approving Authority of the significant deficiency, the supplier:

      1. (a) Does not complete corrective action in accordance with any applicable plan review processes or other Approving Authority guidance and direction, including Approving Authority specified interim actions and measures; or
      2. (b) Is not in compliance with an approved corrective action plan and schedule.

   2. (2) Unless the Approving Authority invalidates a fecal indicator-positive ground water source sample under Regulation .11-2G of this chapter, a ground water system is in violation of the treatment technique requirement if, within 120 days, or earlier if directed by the Approving Authority, of meeting the conditions of §C(1) or (2) of this regulation, the supplier:

      1. (a) Does not complete corrective action in accordance with any applicable plan review processes or other Approving Authority guidance and direction, including Approving Authority-specified interim measures, or
      2. (b) Is not in compliance with an Approving Authority approved corrective action plan and schedule.
   3. (3) A ground water supplier subject to the requirements of Regulation .11D(3) of this chapter that fails to maintain 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 a ground water source is in violation of the treatment technique requirement if the failure is not corrected within four hours of determining the supplier is not maintaining at least 4-log treatment of viruses before or at the first customer.
   4. (4) Ground water suppliers shall give public notification under Regulation .20C(1)(f) of this chapter for the treatment technique violations specified in §D(1)-(3) of this regulation.

Authority: Environment Article, Title 9, Subtitles 2 and 4, Annotated Code of Maryland

Effective date: October 21, 1977 (4:22 Md. R. 1670)

Appendix E adopted effective January 27, 1978 (5:2 Md. R. 84)

Regulations .01, .06—.11, .15A, .19A and B, .20F, and .22 amended effective August 10, 1987 (14:16 Md. R. 1774)

Regulations .15G—P, .19E, .28—.33, and .35 adopted effective August 10, 1987 (14:16 Md. R. 1774)

Regulations .26, .27, and .34 adopted effective November 30, 1987 (14:24 Md. R. 2555)

Appendices A—E recodified as Regulation .36

Chapter recodified from COMAR 10.17.07 to COMAR 26.04.01

Chapter revised effective March 18, 1991 (18:5 Md. R. 596)

Regulation .01B amended effective December 21, 1992 (19:25 Md. R. 2208)

Regulation .03A amended effective December 21, 1992 (19:25 Md. R. 2208)

Regulation .04A amended effective December 21, 1992 (19:25 Md. R. 2208)

Regulation .05-2 adopted effective December 21, 1992 (19:25 Md. R. 2208)

Regulation .08 amended effective December 21, 1992 (19:25 Md. R. 2208)

Regulation .10 repealed and new Regulation .10 adopted effective December 21, 1992 (19:25 Md. R. 2208)

Regulation .11 repealed and new Regulation .11 adopted effective December 21, 1992 (19:25 Md. R. 2208)

Regulation .11-1—.11-3 adopted effective December 21, 1992 (19:25 Md. R. 2208)

Regulation .12 amended effective December 21, 1992 (19:25 Md. R. 2208)

Regulation .17 amended effective December 21, 1992 (19:25 Md. R. 2208)

Regulation .20A, F amended effective December 21, 1992 (19:25 Md. R. 2208)

Regulation .33 amended effective December 21, 1992 (19:25 Md. R. 2208)

Chapter revised effective January 2, 1995 (21:26 Md. R. 2192)

Regulation .01B amended effective October 4, 1999 (26:20 Md. R. 1548); October 16, 2000 (27:20 Md. R. 1842)

Regulation .03A amended effective October 16, 2000 (27:20 Md. R. 1842)

Regulation .04 amended effective October 16, 2000 (27:20 Md. R. 1842)

Regulation .12 amended effective October 16, 2000 (27:20 Md. R. 1842)

Regulation .15 amended effective October 16, 2000 (27:20 Md. R. 1842)

Regulation .15-1 amended effective October 16, 2000 (27:20 Md. R. 1842)

Regulation .15-2 amended effective October 16, 2000 (27:20 Md. R. 1842)

Regulation .20-1 amended effective October 16, 2000 (27:20 Md. R. 1842)

Regulation .20-2 adopted effective October 16, 2000 (27:20 Md. R. 1842)

Regulation .23C adopted effective October 16, 2000 (27:20 Md. R. 1842)

Regulation .29D adopted effective October 16, 2000 (27:20 Md. R. 1842)

Regulation .31 repealed effective October 16, 2000 (27:20 Md. R. 1842)

Regulation .36 adopted effective October 4, 1999 (26:20 Md. R. 1548)

Chapter revised as an emergency provision effective January 1, 2002 (29:4 Md. R. 415); revised permanently effective April 29, 2002 (29:8 Md. R. 702)

Chapter revised effective September 1, 2003 (30:17 Md. R. 1205)

Regulation .01B amended effective April 25, 2005 (32:8 Md. R. 743); December 14, 2009 (36:25 Md. R. 1956); August 29, 2016 (43:17 Md. R. 957)

Regulation .01-1 amended effective April 25, 2005 (32:8 Md. R. 743)

Regulation .01-1B amended effective December 14, 2009 (36:25 Md. R. 1956); March 7, 2011 (38:5 Md. R. 319); August 29, 2016 (43:17 Md. R. 957)

Regulation .03A amended effective August 29, 2016 (43:17 Md. R. 957)

Regulation .04A amended effective August 29, 2016 (43:17 Md. R. 957)

Regulation .05F adopted effective March 7, 2011 (38:5 Md. R. 319)

Regulation .05-2 amended effective April 25, 2005 (32:8 Md. R. 743)

Regulation .15-2I amended effective August 29, 2016 (43:17 Md. R. 957)

Regulation .05-2L adopted effective December 14, 2009 (36:25 Md. R. 1956)

Regulation .05-5 adopted effective March 7, 2011 (38:5 Md. R. 319)

Regulation .06-2 amended effective March 7, 2011 (38:5 Md. R. 319)

Regulation .07 amended effective December 14, 2009 (36:25 Md. R. 1956)

Regulation .07-1 amended effective December 14, 2009 (36:25 Md. R. 1956)

Regulation .08E amended effective April 25, 2005 (32:8 Md. R. 743)

Regulation .09C amended effective April 25, 2005 (32:8 Md. R. 743)

Regulation .10 amended effective August 29, 2016 (43:17 Md. R. 957)

Regulation .11 amended effective August 29, 2016 (43:17 Md. R. 957)

Regulation .11D adopted effective March 7, 2011 (38:5 Md. R. 319)

Regulation .11-1 amended effective August 29, 2016 (43:17 Md. R. 957)

Regulation .11-2 amended effective March 7, 2011 (38:5 Md. R. 319); August 29, 2016 (43:17 Md. R. 957)

Regulation .11-3D adopted effective March 7, 2011 (38:5 Md. R. 319)

Regulation .11-4 adopted effective August 29, 2016 (43:17 Md. R. 957)

Regulation .12 amended effective April 25, 2005 (32:8 Md. R. 743)

Regulation .15-2 amended effective April 25, 2005 (32:8 Md. R. 743); December 14, 2009 (36:25 Md. R. 1956); March 7, 2011 (38:5 Md. R. 319)

Regulation .17A amended effective March 7, 2011 (38:5 Md. R. 319)

Regulation .19D amended effective August 29, 2016 (43:17 Md. R. 957)

Regulation .19D, G amended effective March 7, 2011 (38:5 Md. R. 319)

Regulation .20 amended effective April 25, 2005 (32:8 Md. R. 743); December 14, 2009 (36:25 Md. R. 1956); March 7, 2011 (38:5 Md. R. 319)

Regulation .20-1 amended effective March 7, 2011 (38:5 Md. R. 319)

Regulation .20-2 amended effective March 7, 2011 (38:5 Md. R. 319)

Regulation .20C, D amended effective August 29, 2016 (43:17 Md. R. 957)

Regulation .20-2E amended effective December 14, 2009 (36:25 Md. R. 1956); August 29, 2016 (43:17 Md. R. 957)

Regulation .21 amended effective December 14, 2009 (36:25 Md. R. 1956); March 7, 2011 (38:5 Md. R. 319)

Regulation .21H amended effective August 29, 2016 (43:17 Md. R. 957)

Regulation .21I adopted effective August 29, 2016 (43:17 Md. R. 957)

Regulation .23 amended effective December 14, 2009 (36:25 Md. R. 1956)

Regulation .23C amended effective March 7, 2011 (38:5 Md. R. 319)

Regulation .25B amended effective December 14, 2009 (36:25 Md. R. 1956)

Regulation .25C amended effective April 25, 2005 (32:8 Md. R. 743)

Regulation .30B amended effective December 14, 2009 (36:25 Md. R. 1956)

Regulation .34 amended effective March 1, 2004 (31:4 Md. R. 318)