EPA Announces First Meeting on M/DBP Working Group

In November 2021 EPA published a request that the National Drinking Water Advisory County (NDWAC) “….provide advice and recommendations on key issues related to potential revisions to the following Microbial and Disinfection Byproducts (MDBP) rules: Stage 1 and Stage 2 Disinfectants and Disinfection Byproducts Rules, Surface Water Treatment Rule, Interim Enhanced Surface Water Treatment Rule, and Long-Term 1 Enhanced Surface Water Treatment Rule.” At the same time, EPA requested nominations for an M/DBP Rule Revisions Working Group. The M/DBP Rule Revisions Working Group would make recommendations to the full NDWAC. After reviewing the Working Group’s recommendations, the NDWAC would then submit recommendations of possible M/DBP Rule Revisions to EPA.

The first meeting of the M/DBP Working Group will be May 23, 2022 from 11:00 am until 4:00 pm (ET) and will be hosted virtually through Zoom for Government. The meeting is “intended to make introductions among Working Group members; review previous public engagements and Working Group member interview findings; describe the approach to sequencing meeting topics for the meeting series and supporting discussions with technical information; and share goals for Working Group outcomes/impacts.”

Link to register to listen to the May 23, 2022 meeting:

EPA intends to propose revised regulations by July 2024 and publish the final revised regulations by September 2027.

Under the SDWA as amended in 1996, EPA is required to conduct a review of drinking water regulations every six years, and if appropriate, revise specific regulations. Previous six-year reviews were concluded in 2003 and in 2010. In December 2016, EPA announced the completion of its third review of existing drinking water regulations. EPA determined that eight regulations are candidates for regulatory revision. The eight regulations are chlorite, Cryptosporidium, Giardia lamblia, haloacetic acids (HAA5), heterotrophic bacteria, Legionella, TTHM, and viruses. These constituents are currently regulated under the Long-term 2 Enhanced Surface Water Treatment Rule and the Stage 2 Disinfection Byproduct Rule and are referred to as M/DBP regulations.

In October 2020, and during 2021 EPA held a series of public meetings to obtain input on possible revisions to the eight M/DBP regulations.