Upcoming EPA M/DBP Workshops

Introduction.  On October 14th and 15th, 2020 the Environmental Protection Agency (EPA) held a public meeting to obtain input on possible revisions to eight microbial and disinfection byproduct (M/DBP) regulations (chlorite, Cryptosporidium, Haloacetic acids, heterotrophic bacteria, Giardia lamblia, Legionella, Total Trihalomethanes, and viruses).

What’s New. Earlier today, EPA posted updated information on the process for possible revisions to the M/DBP regulations.  The updated information includes the following statement: “Throughout 2021, EPA intends to continue to seek input relevant to any potential rule revisions through a series of public meetings focusing on specific topics identified through public comments and information.”

The EPA website lists seven tentative dates for future meetings in 2021.  The first two dates are in May and June as follows:

May 20, 2021 – topic “Disinfectant Residual Levels and Opportunistic Pathogens (including Legionella)

June 24, 2021 – topic “Regulated and Unregulated Disinfection Byproducts”

Additional tentative dates in 2021 are July 14th, August 10th, September 1st, September 29th and November 9th.  No topics are listed for these dates. Tentative meeting times are 1:00 to 4:00 pm ET.  No additional details on meeting materials or registration are available at this time.

Link to EPA’s Updated M/DBP Information:


Background.  Under the Safe Drinking Water Act 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 a January 2017 Federal Register notice EPA published the results from the third six-year review of contaminants.  The outcome of that review was that EPA considered eight National Primary Drinking Water Regulations as candidates for regulatory revision (the eight regulations listed above).  The 2017 Federal Register publication did not propose specific revisions to any current regulation, but rather began the process.