Md. Code Regs. 26.04.01.10

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

Section 26.04.01.10 - Maximum Contaminant Levels for Microbiological Contaminants in Drinking Water

A. Until March 31, 2016, the maximum contamination level of total coliform is based on the presence or absence of total coliform in each sample, rather than coliform density. The maximum contaminant level for coliform bacteria is exceeded if:

(1) More than 5 percent of the samples collected in any month are positive for total coliform for any supplier of water that collects 40 or more samples a month;

(2) Two or more samples collected in any month are positive for total coliform for any supplier of water that collects less than 40 samples a month;

(3) A total coliform repeat sample is positive following a fecal coliform-positive or E. coli-positive routine sample; or

(4) Any repeat sample is positive for fecal coliform or E. coli.

B. A supplier of water shall determine compliance with §A of this regulation in each month it is required to monitor total coliform by using:

(1) All routine samples required by Regulation .11A of this chapter;

(2) All repeat samples required by Regulation .11-2A and B of this chapter;

(3) Any routine or repeat samples not invalidated under Regulation .11-2C of this chapter; and

(4) All samples taken in compliance with Regulation .11B(1) of this chapter.

C. Special purpose samples, such as those taken to determine whether disinfection practices following pipe replacement or repair have been sufficient, may not be used to determine compliance with §A of this regulation.

D. Until March 31, 2016, the best technology, treatment techniques, or other means of achieving compliance with §A of this regulation are:

(1) Protection of wells from contamination by appropriate placement and construction;

(2) Maintenance of a disinfectant residual throughout the distribution system;

(3) Proper maintenance of the distribution system including pipe replacement, main flushing programs, proper operation of storage tank and reservoirs, and continual maintenance of positive water pressure in the distribution system;

(4) Filtration and disinfection of surface and ground water as described in 40 CFR Part 141, Subpart H; and

(5) The implementation of a local wellhead protection program under the approval of the Approving Authority.

E. Until March 31, 2016, any fecal coliform-positive repeat sample or E. coli-positive routine sample, or any total coliform-positive repeat sample following a fecal coliform-positive or E. coli-positive routine sample, the system is in violation of the MCL for total coliforms. This is a violation that may pose an acute risk to health.

F. Beginning April 1, 2016, a system is in violation of the MCL for E. coli for samples taken under the requirements of Regulation .11-4 of this chapter when any of the conditions below occur. A violation of the MCL for E. coli may pose an acute risk to health. The MCL for E. coli is exceeded if:

(1) The system has an E. coli-positive repeat sample following a total coliform-positive routine sample;

(2) The system has a total coliform-positive repeat sample following an E. coli-positive routine sample;

(3) The system fails to take all required repeat samples following an E. coli-positive routine sample; or

(4) The system fails to test for E. coli when any repeat sample tests positive for total coliform.

G. Until March 31, 2016, a supplier of water shall determine compliance with §§A - B of this regulation for each month in which it is required to monitor for total coliforms. Beginning April 1, 2016, a supplier of water shall determine compliance with the MCL for E. coli in accordance with §F of this regulation for each month in which it is required to monitor for total coliforms.

H. Beginning April 1, 2016, the best technology, treatment techniques, or other means of achieving compliance with the maximum contaminant level for total coliforms in §§A - B of this regulation, and for achieving compliance with the maximum contaminant level for E. coli in §F of this regulation are:

(1) Protection of wells from fecal contamination by appropriate placement and construction;

(2) Maintenance of a disinfectant residual throughout the distribution system;

(3) Proper maintenance of the distribution system including appropriate pipe replacement and repair procedures, main flushing programs, proper operation and maintenance of storage tank and reservoirs, cross connection control, and continual maintenance of positive water pressure in the distribution system;

(4) Filtration and/or disinfection of surface water, as described in subparts H, P, T, and W of 40 CFR § 141, or disinfection of ground water, as described in subpart S of 40 CFR § 141, using strong oxidants such as chlorine, chlorine dioxide, or ozone; and

(5) For systems using ground water, compliance with the requirements of a Wellhead Protection Program developed and implemented under section 1428 of the SDWA.

(I) Pursuant to section 1412 of the SDWA, the technology, treatment techniques, or other means available identified in this section are affordable technology treatment techniques, or other means available to systems serving 10,000 or fewer people for achieving compliance with the maximum contaminant level for total coliforms in §§A and B of this regulation and for achieving compliance with the maximum contaminant level for E. coli in §F of this regulation.

Md. Code Regs. 26.04.01.10

Regulations .10 amended effective August 10, 1987 (14:16 Md. R. 1774)
Regulations .10 and new Regulation .10 adopted effective December 21, 1992 (19:25 Md. R. 2208); amended effective 43:17 Md. R. 957, eff. 8/29/2016