The U.S. Environmental Protection Agency made a big move on April 2, 2026. It published the Draft Sixth Contaminant Candidate List (CCL 6) in the Federal Register. This is the first time the agency officially called microplastics a contaminant group that needs serious research and possibly future rules under the Safe Drinking Water Act (SDWA).

This decision shows a huge change in how the government sees those tiny plastic bits. You can find them in almost every water source now, from mountain springs to city taps. Add this to the new PFAS limits that also start in 2026, and it’s clear American drinking water is entering a whole new era of regulation.

Here’s what you should know about EPA CCL 6, why microplastics are a big deal, and which water treatment systems actually get rid of them.

What’s the EPA Contaminant Candidate List (CCL) All About?

The Contaminant Candidate List is a list of unregulated chemicals and tiny organisms. EPA scientists think they might be a health risk in drinking water. Things on the CCL aren’t regulated yet, but being on the list means they’ll get focused research, data collection, and a formal scientific review. That process can lead to enforceable Maximum Contaminant Levels (MCLs) down the road, sometimes years later.

The EPA updates the CCL every five years, as the SDWA requires. Past lists included chemicals like perchlorate, chromium-6, and PFAS. All of those eventually got regulated. The CCL has proven to be a reliable early warning system for new threats.

• CCL 1 (1998): 60 chemicals, 10 microbes. This led to rules for several disinfection byproducts.
• CCL 2 (2005): 51 chemicals. It flagged perchlorate, which then got health advisory guidance.
• CCL 3 (2009): 116 chemicals. This list included pharmaceuticals as individual compounds for the first time.
• CCL 4 (2016): 97 chemicals. It added cyanotoxins and strontium.
• CCL 5 (2022): This included PFAS as a group, setting the stage for the 2024 PFAS MCL rule.
• CCL 6 (Draft, April 2026): It adds microplastics and pharmaceuticals as groups. That’s a big change in how they’re looking at things.

What the EPA Said on April 2, 2026

The Draft CCL 6 the EPA published marks two historic firsts:

1. Microplastics are now a contaminant group. Instead of listing individual plastic compounds, the EPA is looking at microplastics as a whole. This acknowledges a big challenge: there are thousands of plastic polymer types, and we’re still developing standard ways to detect them.
2. Pharmaceuticals are also a contaminant group. Building on work from CCL 3 and 5, the agency is widening its watch on pharmaceuticals. This includes hormones, antibiotics, and other drug residues that can slip through regular wastewater treatment.

This announcement opened a 60-day public comment period, which closes on June 2, 2026. The EPA expects to finalize CCL 6 by November 17, 2026, after talking with its independent Science Advisory Board (SAB).

It’s important to note that the U.S. Department of Health and Human Services (HHS) also announced a $144 million investment in a new microplastics research program. This money will help measure plastics in human tissue, check out health impacts, and explore ways to remove them. This coordinated federal effort means microplastics regulation, while still years away, is now moving faster.

“EPA is taking bold action to ensure drinking water is safe from microplastics, pharmaceuticals, and potential hidden contaminants.”

U.S. Environmental Protection Agency, April 2, 2026

Why Microplastics in Drinking Water Are a Big Deal

Microplastics, usually plastic particles smaller than 5 millimeters, show up in almost every water source scientists test globally. That includes deep ocean samples, Arctic ice cores, and even remote mountain springs. Studies in scientific journals have found them in human blood, lung tissue, breast milk, and even fetal placental tissue.

Where Do Microplastics in Water Come From?

• Plastic breaking down: Bottles, packaging, and synthetic clothes break into tiny micro- and nano-sized pieces over time from sun exposure and wear and tear.
• Wastewater discharge: Regular city wastewater treatment removes about 70-80% of microplastics, but the rest goes into our surface water.
• Stormwater runoff: Rain washing over roads carries tire rubber bits, synthetic fibers from clothes, and broken single-use plastics into waterways.
• Farm sources: Plastic mulch film, irrigation pipes, and applying biosolids put plastics directly into soil and groundwater.

Known and Suspected Health Effects

Scientists are still figuring out all the health effects of microplastics, but the evidence is building. Key worries include:

Health Concern	Mechanism	Status of Evidence
Inflammation	Physical irritation from particles in tissues	Strong in animal studies; human studies are ongoing
Endocrine disruption	Plasticizers (phthalates, BPA) leaking from plastic particles	Well-documented for specific compounds
Oxidative stress	Free radicals created by nano-plastic fragments	Lab evidence; limited human data
Gut microbiome disruption	Building up in intestinal tissue	Emerging – studies from 2024-2025
Cardiovascular risk	A 2024 NEJM study linked plaque microplastics to heart attack/stroke risk	Significant – human group data

A major 2024 study in the New England Journal of Medicine found microplastics and nanoplastics in arterial plaque samples. It linked their presence to a 4.5-times higher risk of heart attack, stroke, or death over a three-year period. This was the first big human clinical evidence connecting microplastics to heart and blood vessel problems.

Microplastics and PFAS: A Double Challenge for 2026 Rules

The CCL 6 microplastics announcement comes right as the EPA’s first-ever enforceable PFAS limits go into effect. Public water systems must meet these by 2027:

• PFOA and PFOS: Maximum Contaminant Level (MCL) is set at 4 parts per trillion (ppt).
• PFHxS, PFNA, HFPO-DA: MCL is 10 ppt each.
• EU Drinking Water Directive: Requires PFAS monitoring starting in 2026 across all EU countries.

The global market for PFAS treatment is expected to hit $2.1 billion in 2026 and grow to $3.4 billion by 2033 as rules get stricter worldwide. We expect microplastics regulation to follow a similar path: starting with candidate listing, then monitoring requirements, and finally, MCLs.

For water treatment plant operators and building owners, the lesson from PFAS is clear: start looking at your microplastic removal options now. Don’t wait until binding regulations force you to rush compliance.

Can Water Treatment Systems Get Rid of Microplastics?

Good news: Reverse osmosis systems and ultrafiltration membranes can effectively remove microplastics from drinking water. The key is how small the membrane pores are compared to the particle size.

Reverse Osmosis (RO) – The Best Method

Reverse osmosis membranes have tiny pores, about 0.0001 microns (1 angstrom). That’s much smaller than even the tiniest microplastic particles. RO membranes remove:

• Microplastics (5mm down to 1 micron) – over 99% removal
• Nanoplastics (smaller than 1 micron) – very high removal efficiency
• PFAS compounds – also removes them at over 95% efficiency
• Heavy metals, dissolved solids, bacteria, and viruses

AMPAC USA builds commercial and industrial reverse osmosis systems for everything from small point-of-use needs to large city-wide treatment. Our systems process water at commercial capacity and meet or beat NSF/ANSI 58 standards for reducing contaminants.

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Ultrafiltration (UF) and Nanofiltration (NF)

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Ultrafiltration membranes (pore size 0.01-0.1 microns) remove microplastics >0.1 microns effectively, but allow smaller nano-scale particles to pass. Nanofiltration (0.001 microns) bridges the gap between UF and RO. Both technologies are used in municipal pre-treatment and industrial water reuse applications.

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Conventional Treatment Limitations

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Standard coagulation-flocculation-sedimentation – the backbone of most municipal water treatment – removes approximately 70-80% of microplastics by mass but is ineffective against smaller particles and nanoplastics. Activated carbon alone does not physically retain microplastics, though it can adsorb some plastic-associated chemical pollutants.

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The CCL 6 Comment Period: What Stakeholders Should Do

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EPA’s 60-day public comment period (ending June 2, 2026) is an opportunity for water utilities, industries, municipalities, and citizens to submit scientific data and technical comments to shape how microplastics are ultimately defined and regulated.

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Key issues that remain unresolved and are open for public input:

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• Case definition: What particle size range and polymer types will be regulated? Will nanoplastics be included?

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• Analytical methods: No validated standardized method for microplastic quantification in drinking water exists yet – EPA must develop one before MCLs can be enforced

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• Lab capacity: Certified laboratories capable of reliable microplastic analysis at ppb or ppt levels are limited nationally

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• Treatment feasibility: Costs and technical requirements for large water systems to achieve very low microplastic concentrations need to be assessed

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What Water Treatment Facilities Should Do Right Now

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Even without binding MCLs for microplastics, proactive water quality managers should take these steps now:

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1. Conduct baseline microplastic monitoring. Document current levels in source and finished water using available analytical methods. This data will be valuable for future regulatory compliance demonstrations.

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2. Evaluate membrane treatment upgrades. Facilities currently using conventional treatment should assess the cost-benefit of adding UF or RO polishing stages. These investments address PFAS compliance simultaneously.

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3. Review PFAS compliance status. The April 2027 PFAS compliance deadline is approaching. Membrane-based treatment planned for PFAS removal will also provide microplastic co-removal benefit.

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4. Submit public comments to EPA. Water system operators have until June 2, 2026 to provide technical input on CCL 6. Practical operational feedback from the field is valuable to the rulemaking process.

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5. Train operations staff. Keep staff informed on emerging regulatory developments. Early awareness enables planning for equipment procurement and budget allocation cycles.

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AMPAC USA Water Treatment Solutions for Microplastic Removal

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AMPAC USA, Manufactured in North America at our Woods Cross, Utah facility, designs and builds commercial reverse osmosis systems and industrial RO systems engineered for today’s most challenging water quality requirements – including PFAS, microplastics, nitrates, heavy metals, and dissolved solids.

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Our membrane systems are designed to exceed current and anticipated regulatory standards, protecting municipalities, manufacturers, schools, hospitals, and commercial facilities from emerging contaminants before they become mandates.

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Whether you need a 250 GPD commercial RO unit for a restaurant or a multi-million-gallon industrial system for a manufacturing facility, AMPAC USA engineers a solution matched to your flow rate, source water chemistry, and regulatory requirements.

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Contact AMPAC USA today at (909) 762-8020 or visit our website to speak with a water treatment engineer about your microplastic removal and PFAS compliance needs.

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Frequently Asked Questions About Microplastics in Drinking Water (2026)

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Q: Does my tap water contain microplastics right now?

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Likely yes, in small amounts. Studies have found microplastics in treated tap water across the United States and globally, though concentrations vary widely by source, treatment method, and pipe infrastructure age. The EPA CCL 6 listing means federal data collection on tap water levels will intensify in 2026-2027.

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Q: Are microplastics regulated in drinking water today?

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No. As of April 2026, there is no legally enforceable MCL for microplastics in U.S. drinking water. The EPA’s CCL 6 draft listing is a precursor to potential future regulation – the process typically takes 5-10 years from candidate listing to enforceable standard.

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Q: Does boiling water remove microplastics?

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No. Boiling water does not remove microplastics – it can actually increase their concentration as water volume reduces through evaporation. Physical filtration (reverse osmosis, nanofiltration, or ultrafiltration) is required to remove particles.

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Q: Does a standard pitcher filter (like Brita) remove microplastics?

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Activated carbon pitcher filters are not designed or certified for microplastic removal. Their pore sizes are far too large to reliably capture plastic particles. For effective microplastic reduction, NSF-certified reverse osmosis or ultrafiltration systems are the recommended options.

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Q: When will the EPA set a legal limit (MCL) for microplastics?

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There is no set timeline. EPA must first finalize CCL 6 (expected November 2026), then conduct regulatory determinations (typically 2-3 years), develop analytical methods, and complete cost-benefit analysis before proposing an MCL. Realistically, a proposed MCL for microplastics is unlikely before 2030-2032. However, state-level standards may emerge earlier.

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Q: Which reverse osmosis systems does AMPAC USA recommend for microplastic removal?

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AMPAC USA’s full line of commercial RO systems and industrial RO systems use high-rejection TFC membranes that remove microplastics, PFAS, dissolved solids, and heavy metals simultaneously. For point-of-use protection at home, our residential under-sink RO systems provide effective microplastic removal. Call (909) 762-8020 for a system recommendation based on your water quality report.

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Q: How is the EPA CCL 6 different from PFAS regulations?

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PFAS already have enforceable MCLs (set in 2024, compliance by April 2027). Microplastics on CCL 6 are at an earlier stage – candidate listing, not yet regulated. Think of CCL 6 as the starting gun, while PFAS is already in the final sprint toward compliance.