What You Should Know About Microplastics in Drinking Water

From Environmental Concern to a Public Health Concern

We sat down with our in-house Water Quality Association (WQA) Certified Specialist, A.G., to discuss his takeaways from a WQA lecture titled “The Microplastics Issue – The Next PFAS?”

A.G. has continuing education credits dating back to 2015 and has been attending WQA conferences for many years. He describes himself as a student of Water Quality and is excited to share what he has learned with us today.

His main takeaway: Microplastics are moving from environmental curiosity to increasingly being studied for potential public health implications.

In this blog, we’ll go over what he learned, including emerging health risks of microplastics, regulatory development around microplastics, water filtration technologies that can help with microplastics, and other important information you should know.

Why Microplastics are Difficult to Address

Microplastic exposure is widespread, and avoiding it entirely can be difficult. Tiny plastic particles are present in many environments and products, making it difficult to identify their sources. It’s in packaging, clothing fibers, consumer products (including food and drinks), and industrial materials, and has been detected in many water sources, including some tap water supplies in the U.S.

Microplastic pollution can have so many possible origins; assigning responsibility is complex. Similar to PFAS contamination, sensitivity around origins can create challenging litigation landscapes.

Microplastics and Human Health

A 2024 breakthrough study by the New England Journal of Medicine found that micro and nanoplastics (MNPs) present in arterial plaque correlated to a 4.5x higher risk of heart attack, stroke, or death.

This study is among the first large-scale investigations to explore a potential link between microplastics and cardiovascular risk. Microplastic contamination is increasingly being evaluated as a potential human health concern.

While it found a strong correlation, it does not establish causation, and more research is needed to understand real-world exposure risks.

Microplastics as Chemical Carriers

Many microplastics are hydrophobic and have large surface areas, which means they can adsorb other contaminants onto their surfaces. In water, they can bind various pollutants, including some PFAS ‘forever chemicals,’ certain heavy metals, and other industrial chemicals, depending on the plastic type and water chemistry.

Exposure to microplastics in water may mean they act as carriers for other contaminants under certain conditions. Here’s how it could work:

1. Microplastics can absorb toxic chemicals in the environment.
2. Some of the absorbed chemicals may then be released and become available in the body.

Microplastics are being studied for potential health effects and may also serve as carriers that expose humans to other harmful contaminants. This combined exposure can have a potential impact on human health, though research is still evolving.

The Importance of Filtration Standards

Historically, water filtration claims are inconsistent. Many products advertise benefits like “advanced filtration” or “purification technology,” which is vague to say the least. Rather than trusting bold marketing claims, prioritize water filter certifications.

Microplastics are an emerging contaminant. When searching for a solution to reduce microplastics in your water, look for filters certified to NSF/ANSI Standard 401 and microplastic-reduction claims when available.

About NSF 401 Standard

NSF/ANSI 401 relies on tests using 0.5–1.0 micron particles as surrogates, and certified, high-quality filters (often RO or ultrafiltration) must achieve at least about 85% reduction in this size range, which supports effective removal of many microplastic particles.

Effective Technologies for Reducing Microplastics in Water

Reverse osmosis (RO) water filtration systems are among the most advanced and effective household technologies for removing microplastics and many other contaminants.

 Reverse Osmosis Water Filtration Systems

When it comes to microplastics, an RO membrane plays a central role. Typically, an RO membrane filter contains extremely small pores that can remove particles as small as 0.0001 microns. Microplastics are typically defined as plastic particles up to about 5,000 microns (5 millimeters), with many definitions using a lower size limit around 1 micron, and smaller particles sometimes classified as nanoplastics.

Because microplastics span a broad size range, RO systems are widely considered one of the most effective household technologies for removing microplastic particles from water.

Maintenance is Key

Even the highest-performing water filtration systems have limitations. Filtration media degrades over time as it retains contaminants, requiring replacement. If the system or filters are not maintained, this can lead to clogged filters, membrane failure, and degradation of the filter media.

If not properly maintained, filters can become less effective and, in some cases, may contribute to water quality issues. Your RO system’s performance will depend on consistent maintenance and timely filter replacement.

Federal Oversight is Catching Up

Starting in 2027, the Environmental Protection Agency (EPA) will begin its Unregulated Contaminant Monitoring Rule (UCMR) 6 initiative. This is a mandatory monitoring program for up to 30 unregulated contaminants in US public water systems. In 2026, petitions were submitted to include microplastics, and the EPA has been actively considering whether to add them to the UCMR 6 list. The good news is that this initiative will help inform future US water safety regulations.

If approved, the UCMR 6 will require public water supply utilities to test for microplastics and report contamination levels. The monitoring will begin in 2027 and continue through 2031. This will provide national transparency about microplastics in drinking water.

The Testing for Microplastics Challenge

At this time, there are limited options for microplastics testing. Specialized laboratory equipment is required for microplastic analysis. This creates a data gap between scientific knowledge and consumer awareness.

The Microplastics Issue – Are There Parallels to PFAS?

There are many striking similarities between the two, including widespread contamination, unclear sources, evolving science, and delayed regulatory response. Emerging science suggests microplastics may interact with other contaminants, making them uniquely complex.

Closing Reflection

A.G. admits that he’s still learning about the issue, but this lecture helped him understand how quickly the science is evolving. Microplastics are no longer just an environmental curiosity; they’re becoming a serious topic in public health conversations.

Will microplastics become “the next PFAS”? That answer is still uncertain. We cannot just ask whether it’s present in our water; we need to know how quickly we can respond once we fully understand the risks.