[Code of Federal Regulations]

[Title 40, Volume 22]

[Revised as of July 1, 2005]

From the U.S. Government Printing Office via GPO Access

[CITE: 40CFR141.63]



[Page 437]

 

                   TITLE 40--PROTECTION OF ENVIRONMENT

 

         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)

 

PART 141_NATIONAL PRIMARY DRINKING WATER REGULATIONS--Table of Contents

 

     Subpart G_National Primary Drinking Water Regulations: Maximum 

       Contaminant Levels and Maximum Residual Disinfectant Levels

 

Sec. 141.63  Maximum contaminant levels (MCLs) for microbiological 

contaminants.



    (a) The MCL is based on the presence or absence of total coliforms 

in a sample, rather than coliform density.

    (1) For a system which collects at least 40 samples per month, if no 

more than 5.0 percent of the samples collected during a month are total 

coliform-positive, the system is in compliance with the MCL for total 

coliforms.

    (2) For a system which collects fewer than 40 samples/month, if no 

more than one sample collected during a month is total coliform-

positive, the system is in compliance with the MCL for total coliforms.

    (b) Any fecal coliform-positive repeat sample or E. coli-positive 

repeat sample, or any total coliform-positive repeat sample following a 

fecal coliform-positive or E. coli-positive routine sample constitutes a 

violation of the MCL for total coliforms. For purposes of the public 

notification requirements in subpart Q, this is a violation that may 

pose an acute risk to health.

    (c) A public water system must determine compliance with the MCL for 

total coliforms in paragraphs (a) and (b) of this section for each month 

in which it is required to monitor for total coliforms.

    (d) The Administrator, pursuant to section 1412 of the Act, hereby 

identifies the following as the best technology, treatment techniques, 

or other means available for achieving compliance with the maximum 

contaminant level for total coliforms in paragraphs (a) and (b) of this 

section:

    (1) Protection of wells from contamination by coliforms 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 tanks and 

reservoirs, and continual maintenance of positive water pressure in all 

parts of the distribution system;

    (4) Filtration and/or disinfection of surface water, as described in 

subpart H, or disinfection of ground water using strong oxidants such as 

chlorine, chlorine dioxide, or ozone; and

    (5) For systems using ground water, compliance with the requirements 

of an EPA-approved State Wellhead Protection Program developed and 

implemented under section 1428 of the SDWA.



[54 FR 27566, June 29, 1989; 55 FR 25064, June 19, 1990, as amended at 

65 FR 26022, May 4, 2000]