2026-06662Proposed RuleWallet

EPA Drafts List of 75 Sneaky Chemicals Threatening Your Tap Water

Published Date: 4/6/2026

Proposed Rule

Summary

The EPA just shared a draft list of 75 chemicals, 4 groups of substances, and 9 microbes that might show up in our drinking water and could need new safety rules. This affects everyone who drinks public water, and the EPA wants your thoughts by June 5, 2026, before making final decisions. While no new costs or rules are set yet, this list helps plan future protections to keep our water safe and clean.

Analyzed Economic Effects

7 provisions identified: 7 benefits, 0 costs, 0 mixed.

EPA publishes draft CCL 6 list

The EPA published a draft Sixth Contaminant Candidate List (CCL 6) that includes 75 chemicals, 4 chemical groups, and 9 microbes — 88 contaminants in total — that are not currently regulated but are known or anticipated to occur in public water systems. The list is a planning step to prioritize research and possible future protections for people who drink public water.

CCL guides future monitoring and rules

The CCL is the first step in a larger Safe Drinking Water Act process: it helps the EPA pick contaminants to include in future Unregulated Contaminant Monitoring Rules (UCMR) and to make regulatory determinations. By law the EPA issues a UCMR every five years with no more than 30 contaminants for public water systems to monitor, and the EPA must make regulatory determinations for at least five contaminants from the CCL every five years.

PFAS listed as a broad chemical group

The EPA proposes listing per- and polyfluoroalkyl substances (PFAS) as a group on the draft CCL 6 using the structural definition carried from CCL 5, and excluding PFAS that are already subject to national drinking water regulations. The Agency explains that evaluating thousands of PFAS individually is impractical and the group listing will guide prioritization and science-building for this broad class.

No immediate rules or costs

The EPA states that the draft CCL 6 and the final CCL 6 will not impose any requirements on regulated entities (public water systems) when published. That means there are no new compliance rules or monitoring mandates that take effect as a result of publishing the draft list.

Microplastics listed; major data gaps noted

The EPA included microplastics as a chemical group on the draft CCL 6 but says there are significant data gaps — including lack of a health-based definition, lack of validated detection methods, unknown combined-exposure effects, and incomplete source information — and more research is needed before risks from drinking water can be fully understood. The listing signals the Agency will prioritize research to fill these gaps.

Disinfection byproducts group and four additions

The EPA proposes listing disinfection byproducts (DBPs) as a group on the draft CCL 6, which includes 27 unregulated DBPs; 23 of these were carried from CCL 5 and four (bromochloroacetonitrile, chloral hydrate, chloronitramide anion, and trichloroacetonitrile) are newly added to the group. The group listing signals the Agency will evaluate DBPs further to determine any need for regulation.

Pharmaceuticals group and health benchmarks

The EPA proposes listing pharmaceuticals as a group on the draft CCL 6 (defined to include substances that meet the FD&C Act 'drug' definition) and used newly completed Human Health Benchmarks for Pharmaceuticals (HHB-Rx) to help screen and prioritize pharmaceutical candidates for the list. The listing seeks to focus research and monitoring on pharmaceuticals that may occur in drinking water and pose public health concerns.

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Key Dates

Published Date
Comments Due
4/6/2026
6/5/2026

Department and Agencies

Department
Independent Agency
Agency
Environmental Protection Agency
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