[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: 40CFR141.65]



[Page 438]

 

                   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. 141.65  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 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]