[Code of Federal Regulations]
[Title 40, Volume 19]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR141.65]

[Page 430-431]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 141--NATIONAL PRIMARY DRINKING WATER REGULATIONS--Table of Contents
 
Subpart G--National Revised Primary Drinking Water Regulations: Maximum 
       Contaminant Levels and Maximum Residual Disinfectant Levels
 
Sec. 141.65  Maximum residual disinfectant levels.

    (a) Maximum residual disinfectant levels (MRDLs) are as follows:

------------------------------------------------------------------------
          Disinfectant residual                     MRDL (mg/L)
------------------------------------------------------------------------
Chlorine................................  4.0 (as Cl2).
Chloramines.............................  4.0 (as Cl2).
Chlorine dioxide........................  0.8 (as ClO2).
------------------------------------------------------------------------

    (b) Compliance dates. (1) CWSs and NTNCWSs. Subpart H systems 
serving 10,000 or more persons must comply with this section beginning 
January 1, 2002. Subpart H systems serving fewer than 10,000 persons and 
systems using only ground water not under the direct influence of 
surface water must comply

[[Page 431]]

with this subpart beginning January 1, 2004.
    (2) Transient NCWSs. Subpart H systems serving 10,000 or more 
persons and using chlorine dioxide as a disinfectant or oxidant must 
comply with the chlorine dioxide MRDL beginning January 1, 2002. Subpart 
H systems serving fewer than 10,000 persons and using chlorine dioxide 
as a disinfectant or oxidant and systems using only ground water not 
under the direct influence of surface water and using chlorine dioxide 
as a disinfectant or oxidant must comply with the chlorine dioxide MRDL 
beginning January 1, 2004.
    (c) 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 
residual disinfectant levels identified in paragraph (a) of this 
section: control of treatment processes to reduce disinfectant demand 
and control of disinfection treatment processes to reduce disinfectant 
levels.

[63 FR 69465, Dec. 16, 1998, as amended at 66 FR 3776, Jan. 16, 2001]