1. A. A supplier of water using a surface water source or a ground water source under the direct influence of surface water shall provide treatment that complies with the treatment technique requirements of 40 CFR Part 141, Subparts H, P, and T. The treatment requirements mandate installing and properly operating water treatment processes that reliably achieve:

   1. (1) At least 99.9 percent removal or inactivation, or both, of Giardia lamblia cysts between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer;
   2. (2) At least 99.99 percent removal or inactivation, or both, of viruses between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer; and
   3. (3) At least 99 percent removal of Cryptosporidium between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer for filtered systems, or control of Cryptosporidium in accordance with and in compliance with an approved watershed control plan for unfiltered systems.

2. B. A supplier of water using a surface water source or a ground water source under the direct influence of surface water that serves at least 10,000 individuals shall meet the:

   1. (1) Requirements for avoiding filtration set forth in 40 CFR §§141.71 and 141.171 and the disinfection requirements set forth in 40 CFR §§141.72 and §141.172; or
   2. (2) Filtration requirements set forth in 40 CFR §§141.73 and §141.173 and the disinfection requirements set forth in 40 CFR §§141.72(b) and §141.172.

3. C. A supplier of water using a surface water source or a ground water source under the direct influence of surface water that serves fewer than 10,000 individuals shall meet the:

   1. (1) Requirements for avoiding filtration set forth in 40 CFR §141.71 and the disinfection requirements set forth in 40 CFR §141.72; or
   2. (2) Filtration requirements set forth in 40 CFR §141.73 and the disinfection requirements set forth in 40 CFR §141.72.

4. D. Beginning January 1, 2005, a supplier of water using a surface water source or a ground water source under the direct influence of surface water that serves fewer than 10,000 individuals shall also meet the:

   1. (1) Additional requirements for avoiding filtration set forth in 40 CFR §§141.520—141.522 and the additional disinfection requirements set forth in 40 CFR §§141.530 — 141.544; or
   2. (2) Additional filtration requirements set forth in 40 CFR §§141.550—141.553 and 141.560—141.564 and the additional disinfection requirements set forth in 40 CFR §§141.72 and 141.530—141.544.
5. E. A supplier of water at a system that uses a surface water source or a ground water source under the direct influence of surface water shall comply with the applicable reporting and record keeping requirements in 40 CFR §§141.75, 141.175, and 141.570—141.571.
6. F. The Approving Authority may require a supplier of water using a surface water source or a ground water source under the direct influence of surface water to filter, if the Approving Authority has determined that the supplier of water would be unable to meet the applicable criteria for avoiding filtration found in 40 CFR §§141.71, 141.171, and 141.521—141.522. The supplier of water shall be notified in writing with reasons given for the Approving Authority's decision.
7. G. If at any time a supplier of water using a surface water source or a ground water source under the direct influence of surface water does not meet the applicable criteria to avoid filtration established in 40 CFR §§141.71, 141.171, and 141.521—141.522, then the supplier is required to monitor, report, filter, and disinfect in accordance with the applicable standards and requirements of the Surface Water Treatment Rule set forth in 40 CFR §§141.72—141.75, Subpart H, §§141.172—141.175, Subpart P, and §§141.530—141.571, Subpart T.
8. H. A supplier of water using a surface water source or a ground water source under the direct influence of surface water who demonstrates to the satisfaction of the Approving Authority that the supplier meets the applicable criteria to avoid filtration of 40 CFR §§141.71, 141.171, and 141.521— 141.522 is also required to disinfect, monitor, and report in accordance with the applicable standards and requirements of 40 CFR §§141.72, 141.74, and 141.75, Subpart H, §§141.172 and 141.175, Subpart P, and §§141.530—141.543 and 141.570—141.571, Subpart T.

9. I. The Approving Authority shall determine if public water systems using ground water are under the direct influence of surface water. The Approving Authority may require suppliers of water to conduct studies, perform sampling, and submit data to enable the Approving Authority to make these determinations. The Approving Authority may also rely on independent studies, hydrogeologic data, or its own studies to make these determinations. The Approving Authority shall determine a source to be under the influence of surface water if that source is at risk to contamination from Giardia lamblia cysts. In general, the Approving Authority shall consider the following evidence in making its determinations:

   1. (1) The concentration of total or fecal coliform in the untreated source water under dry weather and wet weather conditions;
   2. (2) The presence of organisms in the source water that are commonly found in surface water such as protozoa, algae, insects, Giardia lamblia, or other large diameter pathogens;
   3. (3) If there are rapid shifts in source water turbidity levels coincident with rainfall events;
   4. (4) If the results of dye tracer studies demonstrate a close hydrologic connection with surface water;
   5. (5) Results of measurement of hydraulic gradients from nearby surface water bodies to the production well or spring;
   6. (6) The depth and integrity of construction of a well or construction and integrity of a spring box or receiver;
   7. (7) Results of evaluations at other sources under similar conditions;
   8. (8) Evidence of disease outbreaks in the population served by the system;
   9. (9) Past violations of coliform bacteria maximum contaminant levels;
   10. (10) Results of on-site inspections; and
   11. (11) Whether the well is completed in a confined aquifer as defined in COMAR 26.04.04 and whether the well was constructed in accordance with COMAR 26.04.04.

10. J. If the Approving Authority has determined that a ground water source is under the direct influence of surface water, the Approving Authority shall notify the supplier of water in writing. The Approving Authority may also notify the supplier of water that the supplier is required to filter, if the Approving Authority has determined that the system would be unable to meet the applicable criteria for avoiding filtration set forth in 40 CFR §§141.71, 141.171, and 141.520—141.522. The Approving Authority shall give the supplier of water the reasons for the Approving Authority's decision. A supplier of water using a ground water source under the direct influence of surface water shall, within:

    1. (1) 6 months after being notified that the supplier's source is under the direct influence of surface water, monitor and report as required by 40 CFR Part 141, Subparts H, P, and T; and

    2. (2) 18 months after being notified that the supplier's source is under the direct influence of surface water:

       1. (a) Meet the applicable criteria to avoid filtration and disinfection requirements of 40 CFR Part 141, Subparts H, P, and T; or
       2. (b) Filter and disinfect in accordance with the applicable standards and requirements of 40 CFR Part 141, Subparts H, P, and T.

11. K. A supplier of water at a system using a surface water source or a ground water source under the direct influence of surface water that did not conduct optional monitoring under 40 CFR §141.172 because they served fewer than 10,000 individuals when the monitoring was required, but serve more than 10,000 individuals before January 1, 2005, shall:

    1. (1) Comply with 40 CFR §§141.170—141.175;
    2. (2) Consult with the Approving Authority to establish a disinfection benchmark; and
    3. (3) Consult with the Approving Authority before making a significant change to its disinfection practice, as defined in 40 CFR §141.172(c)(1)(i)—(iv).

12. L. Testing; Treatment; Record Keeping.

    1. (1) All public water systems using a surface water source or a ground water source under the direct influence of surface water (Subpart H systems) shall comply with 40 CFR §§141.700—141.722, the regulations concerning enhanced treatment for Cryptosporidium.

    2. (2) A supplier of water shall conduct an initial and a second round of source water monitoring for each water treatment facility that treats a surface water or GWUDI source, as set forth in 40 CFR §§141.700—141.706 beginning not later than the month that starts with the date listed in the following table:

       Source Water Monitoring Starting Dates Table
       Systems that serve:	Must begin the first round of source water monitoring not later than the month beginning:	And must begin the second round of source water monitoring not later than the month beginning:
       (a) At least 100,000 people	October 1, 2006	April 1, 2015
       (b) From 50,000 to 99,999 people	April 1, 2007	October 1, 2015
       (c) From 10,000 to 49,999 people	April 1, 2008	October 1, 2016
       (d) Fewer than 10,000 and monitor for E. colia	October 1, 2008	October 1, 2017
       (e) Fewer than 10,000 and monitor for Cryptosporidiumb	April 1, 2010	April 1, 2019

    3. (3) A supplier of water shall monitor on a schedule and in a manner set forth in 40 CFR §§141.701—141.702 and shall:

       1. (a) Submit a sampling schedule for each required round of source water monitoring to the Approving Authority not later than 3 months prior to the applicable date listed in Regulation .05-2L(1) of this chapter for each round of monitoring;
       2. (b) If the Approving Authority does not respond to a water supplier regarding its sampling schedule, sample according to the schedule submitted to the Approving Authority; and
       3. (c) Collect samples within 2 days before or 2 days after the dates indicated in their sampling schedule unless the exceptions identified in 40 CFR §141.702(b)(2)(i) and (ii) apply.
    4. (4) A supplier of water shall collect samples for each plant that treats a surface water or GWUDI source in accordance with 40 CFR §141.703 and shall collect source water samples prior to treatment with chemicals (such as coagulants, oxidants, and disinfectants), unless the system meets the condition of §L(5) of this regulation.
    5. (5) The Approving Authority may approve sampling after chemical treatment if the Approving Authority determines that sampling before treatment is not feasible, and if the Approving Authority determines that chemical treatment is unlikely to have a significant adverse effect on the analysis of the sample.

    6. (6) For the analysis of Cryptosporidium, E. coli, and turbidity, a supplier of water shall:

       1. (a) Use the analytical methods identified in 40 CFR §141.704;
       2. (b) Have the samples analyzed by a laboratory satisfying the criteria set forth in 40 CFR §141.705; and
       3. (c) Conduct the analysis in accordance with 40 CFR §§141.704—141.705.

    7. (7) A supplier of water shall submit its sampling schedules in accordance with 40 CFR §141.702, and shall:

       1. (a) Report source water monitoring results as specified in 40 CFR §§141.706 and 141.721(a) and (d);
       2. (b) Report to the Approving Authority the results from source water monitoring not later than 10 days after the end of the month following the month when the sample is collected; and
       3. (c) If serving at least 10,000 people, report the results from the initial source water monitoring required under 40 CFR §141.707(a) to EPA and the Approving Authority in accordance with 40 CFR §706(b)—(e).
    8. (8) If a supplier of water wishes to use previously collected data to comply with initial source water monitoring, then it shall comply with the grandfathering requirements set forth in 40 CFR §141.707.
    9. (9) A supplier of water shall comply with requirements set forth in 40 CFR §141.708 when making a significant change in disinfection practice.
    10. (10) A supplier of water required to develop disinfection profiles under 40 CFR §141.708 shall comply with 40 CFR §141.709.
    11. (11) A supplier of water shall maintain records of results from the initial round of source water monitoring required under 40 CFR §141.701(a) and the second round of source water monitoring required under 40 CFR §141.701(b) as specified in 40 CFR §141.722(a) and (b).

    ^aApplies only to filtered systems.

    ^bApplies to filtered systems that meet the conditions of 40 CFR §141.701(a)(4) of this section and unfiltered systems.

13. M. Cryptosporidium Treatment Bin Classification for Filtered Systems.

    1. (1) Following completion of initial source water monitoring required under §L(2) of this regulation, filtered systems shall calculate their initial Cryptosporidium treatment bin concentration for each plant by using the following table and as specified in 40 CFR §141.710:

    2. (2) Filtered systems shall report their Cryptosporidium bin classification as specified in 40 CFR §141.710 and shall report their:

       1. (a) Initial bin classification to the Approving Authority not later than 6 months after the system is required to complete initial source water monitoring; and
       2. (b) Second bin classification to the Approving Authority not later than 6 months after the system is required to complete the second round of source water monitoring.

    Bin Classification Table for Filtered Systems

    For systems that are:	With a Cryptosporidium bin concentration of:1	The bin classification is:
    Required to monitor for Cryptosporidium under §141.701	Cryptosporidium < 0.075 oocyst/L	Bin 1.
    	0.075 oocysts/L= Cryptosporidium\< 1.0 oocysts/L	Bin 2.
    	1.0 oocysts/L\= Cryptosporidium\	Bin 3.
    	Cryptosporidium \=3.0 oocysts/L	Bin 4.
    Serving fewer than 10,000 people and NOT required to monitor for Cryptosporidium under §141.701(a)(4)	Not Applicable	Bin 1.

    ¹Based on calculations in §M(2)(a) or (b) of this regulation, as applicable.

14. N. Additional Requirements for Cryptosporidium Treatment.

    1. (1) If a filtered system is required to provide additional treatment under 40 CFR §141.710(a), then it shall provide the level of additional treatment for Cryptosporidium in accordance with 40 CFR §141.711.
    2. (2) Unfiltered systems shall calculate the arithmetic mean of all Cryptosporidium sample concentrations reported under §L of this regulation in accordance with 40 CFR §141.712(a), and shall provide the level of additional treatment for Cryptosporidium required in 40 CFR §141.712(b).
    3. (3) Suppliers of water required to provide additional treatment for Cryptosporidium under 40 CFR §§141.710—141.712 shall provide the treatment required according to the following schedule:
    4. (4) If the bin classification for a filtered system changes following the second round of source water monitoring, filtered systems must recalculate their Cryptosporidium bin concentration and bin classification in accordance with 40 CFR §141.710(d), and the system must provide the level of treatment for Cryptosporidium required under 40 CFR §141.711 on a schedule the State approves.

    Cryptosporidium Treatment Compliance Dates Table

    Systems that serve:	Shall comply with Cryptosporidium treatment requirements not later than:a
    (a) At least 100,000 people	April 1, 2012
    (b) From 50,000 to 99,999 people	October 1, 2012
    (c) From 10,000 to 49,999 people	October 1, 2013
    (d) Fewer than 10,000 people	October 1, 2014

    ^aApproving Authority may allow up to an additional 2 years for complying with the treatment requirement for systems making capital improvements.

15. O. Toolbox Options for Meeting Cryptosporidium Treatment Requirements.

    1. (1) Suppliers of water may obtain treatment credits by complying with the requirements of 40 CFR §§141.715—141.720 for toolbox options including:

       1. (a) Microbial toolbox options, treatment credits, and criteria for meeting Cryptosporidium treatment requirements as set forth in 40 CFR §141.715;
       2. (b) Source toolbox components set forth in 40 CFR §141.716;
       3. (c) Prefiltration treatment toolbox components set forth in 40 CFR §141.717;
       4. (d) Treatment performance toolbox components set forth in 40 CFR §141.718;
       5. (e) Additional filtration toolbox components set forth in 40 CFR §141.719; and
       6. (f) Inactivation toolbox components set forth in 40 CFR §141.720.
    2. (2) Suppliers of water shall report to the Approving Authority as specified in 40 CFR §141.721 for any microbial toolbox options used to comply with treatment requirements under 40 CFR §141.711 or 141.712. Alternatively, for treatment credits, the Approving Authority may approve certifications that demonstrate that a water system is operating within required treatment parameters, rather than to require it to report monthly operational data for tool box options.
    3. (3) Suppliers of water shall keep the results of treatment monitoring associated with microbial toolbox options, as required by 40 CFR §§141.716—141.720, for 3 years.

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)