Regulatory Determination 5

Regulatory Determination 5

The Safe Drinking Water Act (SDWA), as amended in 1996, directs the EPA to publish a list of contaminants (referred to as the Contaminant Candidate List, or CCL) to assist in priority-setting efforts. The SDWA also directs the EPA to select no fewer than five contaminants from the current CCL and determine whether to regulate these contaminants with a National Primary Drinking Water Regulation (NPDWR). A regulatory determination is a decision on whether EPA should initiate a rulemaking process to develop an NPDWR for a specific contaminant. Learn more about the rulemaking process.

Preliminary Regulatory Determinations for Contaminants on the Fifth Contaminant Candidate List

On January 15, 2025, the EPA announced its preliminary regulatory determination for nine contaminants on the Fifth Contaminant Candidate List (CCL 5). The EPA has made preliminary determinations to not regulate the following nine contaminants: 2-aminotoluene, cylindrospermopsin, ethoprop, microcystins, molybdenum, permethrin, profenofos, tebuconazole and tribufos. The EPA will request public comment on these preliminary determinations.

Supporting Materials 

• Federal Register Notice: Announcement of Preliminary Regulatory Determinations for Contaminants on the Fifth Drinking Water Contaminant Candidate List  
• Technical Support Documents for Preliminary Regulatory Determinations 5 are available on www.regulations.gov: Docket ID No. EPA-HQ-OW-2024-0456.