40 CFR 141.65 - Maximum residual disinfectant levels.

§ 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]

This is a list of United States Code sections, Statutes at Large, Public Laws, and Presidential Documents, which provide rulemaking authority for this CFR Part.

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United States Code

Title 40 published on 2015-08-22

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 40 CFR Part 141 after this date.

  • 2017-01-17; vol. 82 # 10 - Tuesday, January 17, 2017
    1. 82 FR 4805 - Use of Lead Free Pipes, Fittings, Fixtures, Solder and Flux for Drinking Water
      GPO FDSys XML | Text
      ENVIRONMENTAL PROTECTION AGENCY
      Proposed rule.
      Comments must be received on or before April 17, 2017.
      40 CFR Parts 141 and 143
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