EPA releases Stage 2 Disinfectant Byproduct Rule

The U.S. Environmental Protection Agency (EPA) has released its proposed Stage 2 Disinfectants and Disinfection Byproducts Rule (DBPR).


Aug. 20, 2003 -- The U.S. Environmental Protection Agency (EPA) has released its proposed Stage 2 Disinfectants and Disinfection Byproducts Rule (DBPR).

The rule is one part of the Stage 2 Microbial and Disinfection Byproducts Rules (M-DBP), which are a set of interrelated regulations that address risks from microbial pathogens and disinfectants/disinfection byproducts (D/DBPs). The Stage 2 M-DBP Rules are the final phase in the M-DBP rulemaking strategy, affirmed by Congress as part of the 1996 Amendments to the Safe Drinking Water Act (SDWA).

The Stage 2 DBPR focuses on public health protection by limiting exposure to DBPs, specifically total trihalomethanes (TTHM) and five haloacetic acids (HAA5), which can form in water through disinfectants used to control microbial pathogens.

The companion rule to the proposed Long-Term 2 Enhanced Surface Water Treatment Rule that was published Aug. 11, the Stage 2 DBPR aims to reduce public exposure to DBP peaks in the distribution systems of community and nontransient-noncommunity systems that provide disinfection (other than by ultraviolet disinfection). As it did with the previous proposed rule, the American Water Works Association (AWWA) has asked EPA to double the 90-day comment period for the Stage 2 DBPR.

This rule will apply to all community water systems (CWSs) and nontransient noncommunity water systems (NTNCWSs) that add a primary or residual disinfectant other than ultraviolet (UV) light or deliver water that has been disinfected by a primary or residual disinfectant other than UV.

In addition to the Stage 2 DBPR, the Stage 2 M-DBP Rules include the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), which focuses on microbial pathogens. To balance risks associated with the control of pathogens and limiting exposure to DBPs, the Stage 2 DBPR and LT2ESWTR are being developed simultaneously.

EPA convened a Federal Advisory Committee to develop recommendations for both the Stage 2 DBPR and the LT2ESWTR. As recommended by the Federal Advisory Committee, the Stage 2 DBPR will propose to modify the requirements of the Stage 1 DBPR by altering monitoring locations and methods for calculating annual average levels of TTHM and HAA5. Monitoring locations will be determined by water systems through the performance of Initial Distribution System Evaluations (IDSEs).

Links to the following resources are available:

Federal Register Notice
HTML version, Part 1: http://www.epa.gov/fedrgstr/EPA-WATER/2003/August/Day-18/w18149a.htm
HTML version, Part 2: http://www.epa.gov/fedrgstr/EPA-WATER/2003/August/Day-18/w18149b.htm
HTML version, Part 3: http://www.epa.gov/fedrgstr/EPA-WATER/2003/August/Day-18/w18149c.htm
PDF version (2.3 MB): http://www.epa.gov/safewater/stage2/pdfs/fr_stage2_full.pdf

Fact Sheet (147KB PDF) (July 2003 EPA 815-F-03-006): http://www.epa.gov/safewater/stage2/pdfs/fact_%20st2_proposed.pdf
Guidance Manuals: http://www.epa.gov/safewater/stage2/guides.html
Prepublication Notice: http://www.epa.gov/safewater/stage2/pdfs/stage2_prepub_fr.pdf

EPA's Stage 2 Disinfectants and Disinfection Byproducts Rule page will be located at:
http://www.epa.gov/safewater/stage2/index.html

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