EPA Unveils Draft List of 75 Potential Drinking Water Contaminants Nationwide
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 are set yet, future rules could impact water providers and communities.
Analyzed Economic Effects
8 provisions identified: 7 benefits, 1 costs, 0 mixed.
Final CCL guides future regulation of 5+ contaminants
The EPA will use the final CCL 6 to prioritize research and data collection and, in a future separate action, will make regulatory determinations on whether to regulate at least five contaminants from the CCL with National Primary Drinking Water Regulations under SDWA section 1412(b)(1)(B)(ii).
PFAS listed as a broad chemical group
EPA proposes listing per- and polyfluoroalkyl substances (PFAS) as a group on the draft CCL 6, using the same structural definition applied in CCL 5 and excluding PFAS that are subject to national drinking water regulations at the time of final CCL 6. The structural definition includes three specific chemical structure patterns described in the document.
Draft CCL 6: 88 contaminants listed
The EPA published a draft Contaminant Candidate List 6 (CCL 6) that includes 75 individual chemicals, 4 chemical groups, and 9 microbes — 88 contaminants in total. These are known or anticipated to occur in public water systems and could be prioritized for future action under the Safe Drinking Water Act.
CCL links to UCMR monitoring (up to 30)
The CCL informs future Unregulated Contaminant Monitoring Rules (UCMR). SDWA section 1445(a)(2) requires EPA to issue a UCMR every five years with a list of no more than 30 unregulated contaminants for public water systems to monitor.
Microplastics listed; major data gaps noted
EPA proposes listing microplastics as a chemical group on the draft CCL 6 and identifies significant data gaps that require research: (1) a health-based definition (characteristics like size, polymer, shape), (2) validated detection technology, (3) understanding microplastics in mixtures, and (4) sources of microplastics contributing to drinking water.
Pharmaceuticals grouped; benchmarks used
EPA proposes listing pharmaceuticals as a chemical group on the draft CCL 6 and used Human Health Benchmarks for Pharmaceuticals (HHB-Rx) to inform screening. For CCL 6 purposes, 'pharmaceuticals' are considered any substances defined as a 'drug' under the Federal Food, Drug, and Cosmetic Act (1938).
No immediate rules for water systems
The draft CCL 6 and the final CCL 6, when published, will not impose any requirements on regulated entities (public water systems). The document is a prioritization and research planning step, not a regulation.
Disinfection byproducts listed as a group
EPA proposes listing disinfection byproducts (DBPs) as one of four chemical groups on the draft CCL 6. The DBP group includes 27 unregulated DBPs — 23 carried from CCL 5 plus 4 additional DBPs (bromochloroacetonitrile, chloral hydrate, chloronitramide anion, and trichloroacetonitrile).
Personalized for You
How does this regulation affect your finances?
Personalize government policy and PRIA will tell you what this federal register document means for your household, plus every other regulation we track. PRIA reads each provision against your financial profile to show you exactly what matters to your wallet.
Key Dates
Department and Agencies
Related Federal Register Documents
2026-19071, Partial Repeal of the Carbon Pollution Standards for Fossil Fuel-Fired Electric Generating Units
The EPA is rolling back most of the 2024 rules that limited carbon pollution from fossil fuel power plants. This change affects coal and gas plants by easing some strict limits on emissions and carbon capture technology. The new rules kick in on November 16, 2026, potentially saving money for power plants but raising questions about pollution control.
2026-19072, Rescission of the Greenhouse Gas Findings for Fossil Fuel-Fired Power Plants and Repeal of Regulations for Power Plant Greenhouse Gas Emissions Under Clean Air Act Section 111
The EPA is proposing to cancel all greenhouse gas rules for fossil fuel power plants, saying the law doesn’t let them regulate these emissions for climate reasons. This change affects power plants across the U.S. and could impact future pollution limits and costs. Comments on this proposal are open until November 2, 2026, so now’s the time to speak up!
2026-18317, Updated Definition of “Waters of the United States”
The purpose of this supplemental notice of proposed rulemaking is for the U.S. Environmental Protection Agency (EPA) and the Department of the Army ("the agencies") to supplement and seek additional comment on certain aspects of an earlier proposal, published on November 20, 2025, to revise the regulations defining the scope of waters federally covered under the Clean Water Act in light of the U.S. Supreme Court's 2023 decision in Sackett v. Environmental Protection Agency. As stated in the agencies' November 20, 2025 Notice of Proposed Rulemaking (NPRM), the agencies intend for this rulemaking to provide greater regulatory certainty and increase Clean Water Act program predictability and consistency by clarifying the definition of "waters of the United States." After consideration of the public comments received on the NPRM, the agencies are issuing this notice to supplement the NPRM with additional regulatory options on certain aspects of the proposed rule.
2026-14112, Amendments and Nonconformance Penalties for Model Year 2027 and Later Heavy-Duty Highway Engines and Amendments to Inducement Provisions for SCR-Equipped Diesel Engines
Starting with model year 2027, the EPA is updating rules for big truck engines to make sure they last longer and pollute less. They’re also letting engine makers pay penalties if their engines don’t meet standards, and tightening rules for special pollution-control systems on diesel engines. These changes affect truck and engine makers and kick in soon, with public feedback due by August 29, 2026.
2026-13667, Minor New Source Review Program Air Permitting Public Participation Requirements for State Implementation Plans
The EPA wants to give states more freedom to decide how much public input is needed when approving small air pollution sources or changes. This means local air agencies can tailor public participation to fit their community’s needs while still protecting air quality. If you’re involved in air permits, watch for comment deadlines and possible virtual hearings this summer!
2026-13263, Revisions To Establish the Sixth Unregulated Contaminant Monitoring Rule (UCMR 6) for Public Water Systems
The EPA is rolling out the sixth Unregulated Contaminant Monitoring Rule (UCMR 6) to check for new, sneaky chemicals in public drinking water. Big water systems serving 3,300+ people and some smaller ones will test for 30 different contaminants, including certain PFAS and pesticides, to keep our water safe. Comments and feedback are open until late August 2026, and the EPA will host fun online meetings to chat about the plan!
Previous / Next Documents
Previous: 2026-06646, Reducing Bureaucracy and Burden for Children, Youth, and Family Programs
The Department of Health and Human Services is making rules for programs that help runaway and homeless youth simpler and easier to understand. These changes cut out extra paperwork and confusing parts, so organizations can focus more on helping kids and families. If you want to share your thoughts, send comments by May 6, 2026—this update aims to save time and make a bigger impact without extra costs.
Next: 2026-06665, Protection of Stratospheric Ozone: Listing of Substitutes Under the Significant New Alternatives Policy Program in Refrigeration and Air Conditioning and Fire Suppression; Supplemental Notice of Proposed Rulemaking
The EPA wants to officially approve a new refrigerant called HFO-1234yf for use in heavy-duty pickup trucks and vans’ air conditioning systems, but with some rules to keep things safe. This update adds details and invites the public to share their thoughts by May 6, 2026. If you’re in the vehicle or refrigeration world, this could affect your choices and costs soon!