EPA seeks input–Sixth Contaminant Candidate List (CCL 6)

The U.S. Environmental Protection Agency (EPA) is requesting nominations for chemicals, microbes, or other substances that are not currently regulated in drinking water for the Sixth Contaminant Candidate List (CCL 6). EPA uses the CCL to identify priority contaminants for future regulatory decision making (i.e., Regulatory Determination Process) and information collection (e.g., Unregulated Contaminant Monitoring Rule). EPA requests that nominations include information showing the nominated contaminant is known or anticipated to occur in public water systems and indicating the nominated contaminant may have an adverse health effect on humans. EPA is requesting nominations and information be sent to the Federal Register using the Docket ID No. EPA-HQ-OW-2022-0946, at https://www.regulations.gov.

The comment period will be open for 60 days after the Notice is published in the Federal Register.


The drinking water CCL is a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations, but are known or anticipated to occur in public water systems. Contaminants listed on the CCL may require future regulation under the Safe Drinking Water Act (SDWA).  Publishing the CCL does not impose any requirements on public water systems. However, if EPA decides to regulate a contaminant – as part of the regulatory determination process – the Agency will start a separate rulemaking process with opportunity for public comment.

Patti Kay Wisniewski (she/her/hers)

Drinking Water Preparedness and Resiliency Coordinator

US EPA Region 3

Drinking Water Section (3WD21)

Four Penn Center

1600 John F. Kennedy Blvd.

Philadelphia, PA 19103-2852

EPA Cell: 215-514-7893

Email: [email protected]

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