PFAS and Microplastics: Are Patterns Repeating?

Over the past decade, PFAS have reshaped the drinking water regulatory landscape. The Fifth Unregulated Contaminant Monitoring Rule (UCMR5) revealed PFAS to be widely present in drinking water across the United States, adding to public outcry amid ongoing federal and state regulation of PFAS in drinking water, while also increasing scrutiny of wastewater and biosolids as potential pathways for PFAS to reenter the environment.

More recently, another emerging water contaminant is making headlines: microplastics. The contaminant is included in the Sixth Contaminant Candidate List (CCL6) to be considered for UCMR6, alongside a broader range of PFAS chemicals.

While no one is certain that microplastics will follow the same regulatory path as PFAS, there are parallel regulatory and public awareness issues between the two contaminant families that water utilities nationwide should be aware of.

The PFAS Regulatory Timeline

PFAS have been used in thousands of different consumer and industrial products for decades, but given the late-developing knowledge by regulators and the public about the risks and even the existence of these compounds, drinking water regulations for PFAS have developed much more recently. Early litigation, growing public concern, and robust federal monitoring eventually helped move PFAS from an emerging contaminant issue into a formal regulatory priority.

A key turning point came during the 2013–2015 UCMR3 monitoring period, when water systems tested for six PFAS chemicals and helped create a clearer national picture of PFAS occurrence in drinking water. Years later, UCMR5 expanded monitoring to a larger group of PFAS chemicals, further increasing attention on the scale of contamination.

That monitoring eventually helped set the stage for EPA’s mandatory drinking water standards for certain forms of PFAS. This history does not mean microplastics will follow the same path, but it does show how monitoring often sets the stage for increased public awareness and regulatory action.

Where Microplastics in Drinking Water Stand

Over 350 million tons of plastic are produced annually in the form of nurdles in cosmetics, nylon thread in clothes, and plastic bottles, among countless other forms. And the production of plastics shows no signs of stopping. As these plastics are discarded, they find their way into the environment and eventually break down into microplastics.

As a result, microplastics are being discovered from Antarctica to our blood streams. They’re a ubiquitous, microscopic pollutant being linked to cancer, heart attacks, and reproductive organ harm.

If approved for inclusion in UCMR6, select water utilities will be testing for microplastics between 2027 and 2031 to collect data on the prevalence of these substances in drinking water. Given the widespread use of microplastics in consumer products, the results of UCMR6 may mirror the findings of UCMR5 as to the prevalence of PFAS.

Microplastics’ inclusion on CCL6 was partially driven by public outcry. Seven state governors sent a petition to the EPA pushing for microplastics to be studied and better understood as they relate to drinking water, while simultaneously proposing state regulatory action on microplastics to get ahead of the federal agenda.

Beyond drinking water, wastewater treatment plants are known emitters of microplastics, as conventional treatment processes do not fully remove them from wastewater streams. Tracking microplastics at wastewater treatment plants could follow a regulatory trend similar to PFAS, from monitoring and testing requirements to effluent limits and restrictions or bans on the disposal of biosolids.

H2: PFAS and Microplastics Regulatory Trends

EPA’s decision to include microplastics as a contaminant group on draft CCL6 is an important early signal for drinking water policy. While microplastics may not follow the same path as PFAS, their inclusion shows that federal agencies are beginning to evaluate them more formally.

PFAS and microplastics have many similarities:  

• Their widespread use in many different products

• Governments and scientists are pushing to study them further

• They are large families of pollutants, not a singular pollutant

Ahead of federal rules, the state of California has created a statewide strategy to address microplastics, going as far as listing it in the state’s drinking water handbook. This move was coupled with the development of two methods for extracting and testing microplastics, as well as the certification of three laboratories to conduct the tests, enabling water utilities to report microplastics. California will also require microplastics levels to be included in consumer confidence reports.

In New Jersey, the 2024 Microplastic Bill focused on removing microplastics from drinking water systems and determining their environmental impact. This includes studies at Rutgers University on the origin and migration, removal technologies and cost estimates, and disposal of microplastics. The study is slated to be completed by 2027.

Despite their similarities, PFAS and microplastics have differences too.

• Measurement and detection variability

• Broader source dispersion

• Existing regulatory stances (both federal and state)

• Identification of effective treatment technologies

Due to these differences and more, regulatory patterns can only be used to help us interpret early signals about the future of microplastics regulations, without guaranteeing that they will follow the same path as PFAS and others before them.

What Water Utilities Should Watch Next

While federal regulation of microplastics remains years away, EPA’s recent actions put the issue on a familiar trajectory that mirrors the early days of PFAS: initial scientific uncertainty, growing public concern, expanding research, and eventual cost and liability questions for water systems.

By placing microplastics on its draft Sixth Contaminant Candidate List, the EPA is not imposing new requirements on water providers today. But it is signaling that microplastics are moving from an emerging concern into the regulatory and policy mainstream.

From a utility perspective, this matters because once contaminants enter the regulatory pipeline, costs inevitably follow. Treatment upgrades, monitoring, and compliance can strain tight municipal budgets. History shows that when contamination becomes widely recognized, utilities are often left to shoulder costs upfront before liability frameworks catch up.

Taking time to understand the contaminants' regulatory cycle can help water utilities plan around upcoming regulations.