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Are Microplastics in Drinking Water?

Are Microplastics in My Drinking Water?—The Ultimate Guide


As we well know by now, plastic never fully breaks down. Instead, it degrades bit by bit into tiny microplastic particles which are free to spread throughout the environment—including drinking water sources. Microplastics in drinking water have quickly attracted attention as a contaminant of emerging concern.

In this ultimate contaminant guide to microplastics, we’ll help you get to the bottom of the matter, unveiling the origins of micro- and nano-plastics, potential health impacts, common misconceptions, the state of regulation and treatment options, and answer some frequently asked questions.

Table of Contents: 

What Are Microplastics?

Microplastics are tiny plastic particles, technically defined as larger than 1 micron (1 μm) and smaller than five millimeters (5 mm) in diameter. Five millimeters is about the size of a sesame seed, though microplastics can be smaller than the period at the end of this sentence.

1mm (millimeter) = 1,000 µm (micron, also known as micrometers)

What Are Nanoplastics?

Nanoplastics are plastic particles that have degraded to less than 1 µm. That’s in the realm of bacteria (~2 µm), and smaller than the average red blood cell (~6-7 µm). This size difference affects their interaction with the environment and potential toxicity​​. Nanoplastics in the environment likely derive from microplastics that have broken down to the even smaller “nano” size category.

microplastics size chart

Are PFAS Microplastics?

No, PFAS—per- and polyfluoroalkyl substances—are not microplastics.

Both PFAS and microplastics are emerging human-made contaminants of environmental concern. PFAS contain thousands of different compounds that can be loosely defined by their structures, which have multiple fluorine atoms bonded to an alkyl chain. They are largely used in non-stick or water resistant products like frying pans, jackets, and food packaging. 

Microplastics are also a complex class of chemicals, but their chemical composition is distinct. Plastics are technically polymers, and they have many applications due to their ability to be shaped when soft and then retain a shape when hardened.

PFAS in Drinking Water: Everything You Need To Know—SimpleLab Tap Score

Where Do Microplastics Come from?

Because much of what we manufacture and use (along with a huge chunk of our waste) contains plastic, microplastics come from a wide variety of sources. They have been detected extensively in sea water, surface waters and drinking water (including tap water and bottled water) around the world.

Primary vs Secondary Microplastics

Primary microplastics are intentionally manufactured microplastics, used in commercial products, such as in cosmetics. They include microbeads, those tiny beads found in face washes and toothpaste, as well as nurdles, small plastic pellets used for manufacturing plastic.

Secondary microplastics are created indirectly as larger plastics break down through physical, chemical, and biological processes​​. These tiny pieces of plastic include stray bits of synthetic fiber from laundered clothes and particles, films, foams, and fragments from the disintegration of plastic waste.

Are Microplastics in Bottled Water?

microplastics are more common in bottled water

Most likely. While not every bottled water brand has been tested, research shows that concentrations of microplastics in water bottles made of plastic are higher than in tap water.

How Do Microplastics Affect Human Health?

As microplastics are a relatively new field of study, the effects of microplastics on human health remain largely unknown. At the moment, both the World Health Organization (WHO) and the Centers for Disease Control & Prevention (CDC) have stated there is insufficient evidence linking microplastics to concrete health effects.

However, potential health impacts from microplastics include the physical hazards of ingestion, their ability to absorb and release toxic chemicals (plastics in general have the ability to absorb toxic chemicals and to leach them out), and the possibility that microplastics themselves could foster the formation or growth of biofilms in distribution systems (which could include harmful pathogens).

Research into microplastics is ongoing. Key areas of discovery include the impact of microplastic exposures depending on their size and material. We’ll cover this in more detail below, but suffice it to say there is less cause for alarm than you might think.

Are Microplastics Regulated?

In the United States, microplastics remain largely unregulated. The only piece of legislation in the field of microplastics is 2015’s Microbead-Free Waters Act. Congress amended the Federal Food, Drug and Cosmetic Act (FD&C) to prohibit the manufacturing, packaging, and distribution of rinse-off cosmetics containing plastic microbeads. This includes cosmetics and OTC (over-the-counter) drugs, such as toothpastes.

Individual states are free to pursue their own legislation. But regulation tends to follow behind research by many years, and as mentioned, microplastics are only recently taking off as a field of study.

How Do You Know if You Have Microplastics in Your Drinking Water?

Microplastics that have entered a water system and made it through a treatment plant to your tap cannot be seen, smelled or tasted. The only way to know if microplastics are in your drinking water is to have your water tested.

How Do Microplastics Get into Drinking Water Systems?

Microplastics get into our drinking water in a few different ways. Water carrying plastics from used products or other trash eventually leads to water sources like rivers, lakes, and reservoirs. Other ways include plastic breaking down directly in the environment, overflow from sewers, particles from the air, and liquid waste from factories and heavy industry.

Does Your Water System Make a Difference?

Microplastics are an issue that affects both public water systems and private wells. Microplastic contamination has reached groundwater and surface water sources—like aquifers, rivers, and lakes—that impact both wells and utilities. 

Water treatment facilities use a variety of treatment technologies, and conventional treatment does remove microplastics to some degree. Removal efficiencies vary substantially, however, and it’s generally understood that conventional drinking water treatment is not very effective at removing smaller microplastics.

Can You Test for Microplastics?

Yes, you can test for microplastics, but tests must be conducted by a certified laboratory. There are no at-home testing options (like strips) that can even identify the presence of microplastics in a sample of water.

How to Test for Microplastics

Testing for microplastics is as simple as collecting a water sample from your faucet and sending it out for analysis. Your test will specify which sampling method is required, but a fully-flushed sample—which is where you run your water for a few minutes to flush your plumbing system to clear out any contaminant buildup from your pipes—is typically called for to shed light on the quality of your water supply, rather than your plumbing.

which microplastics test is right for me?

How Are Microplastics Tested?

When you purchase our microplastics water test kits, our certified lab partners will use a combination of optical microscopy, polarized light microscopy, and Raman spectroscopy to detect microplastics as small as 1 µm. Raman spectroscopy refers to a spectroscopic technique which involves the changes of monochromatic (laser) light as it interacts with a sample of interest. The Advanced Kit breaks microplastics down by size category and polymer type allowing for accurate identification of the specific type or types of plastic in the sample.

Note: Because microplastic analysis is still an emerging field without standardized laboratory protocols, there is not one single standard method or technique that works well for all labs. More details about microplastic testing methods are forthcoming.

Can You Test for Nanoplastics?

Methods to accurately identify nanoplastics (< 1 μm in size) are not yet available to the public. Both the methods and instruments required for nanoplastics detection are highly specialized and largely under development in academic labs.

Should I Be Concerned About Microplastics and Nanoplastics?

As with all “contaminants of emerging concern,” there is a valid reason to be mindful of the potential impacts of micro- and nanoplastics on your health and the environment. But concern is not necessarily cause for alarm.

Although there isn’t enough evidence from a health perspective to raise alarms, staying informed about the latest scientific developments is a wise approach. Beginning with a thorough understanding of your overall water quality is a great place to start.

Understanding your water holistically means learning about a broad range of contaminants—regulated and unregulated—that have known health effects. Prioritizing what you can exercise control over will go a long way toward improving the overall toxicity risk of your water. Contaminants like heavy metals, disinfection byproducts, PFAS, and volatile organic compounds (VOCS) have years of research and proven studies into their sources and treatment options.

Not sure where to get started? Water testing kits—like Tap Score’s Advanced City and Well tests—offer analysis of over 100 contaminants. They also include treatment recommendations for your unique water profile.

By focusing on a broader array of contaminants, you can learn a lot about your overall water quality while finding recommendations for a treatment technology that’s also effective at removing microplastics.

How Do You Remove Microplastics from Your Drinking Water?

Current studies show that microplastics can be removed from your drinking water through membrane filtration.

NSF/ANSI certification 401 requires a filter to reduce microplastics of about  0.5 µm to < 1 µm in size by at least 85 % when operated. However, many filters are actually more efficient. This means there are already off-the-shelf systems for home tap water treatment that can provide adequate protection from microplastics.

When selecting a water filtration technology, you should ensure the filter’s packaging says it is certified under NSF/ANSI standard 401 for the removal of microplastics. Look for the NSF/ANSI seal, or one from WQA or IAPMO. You can also check the filter pore size. Pore sizes of 2.5 µm or less should filter microplastics from your tap water effectively, although it’s worth mentioning there is no one-size-fits-all, best water filter for microplastics.

water filter certification seals

Does Reverse Osmosis (RO) Remove Microplastics?

Yes, reverse osmosis (RO) should effectively remove all or nearly all microplastics. RO works by using high pressure to push water through a semipermeable membrane with very small pores; the pores allow water to pass through but keep many contaminants from doing so.

Note: RO systems use more energy and water than other treatment methods, and they produce a waste stream.

Does Nanofiltration (NF) Remove Microplastics?

Micro-, ultra-, and nanofiltration will remove the majority of microplastics. Specifically, microfiltration rejects particles >1 µm, ultrafiltration rejects particles >0.01 µm, and nanofiltration >0.001 µm.

Does Activated Carbon Filter Microplastics?

Some activated carbon filters can remove microplastics. But to be certain, make sure you only consider filters that are certified to reduce microplastics.

Does Brita Filter Microplastics?

Yes, the Brita Elite Filter is certified under NSF/ANSI 401 to reduce microplastics. However, the Standard Brita pitcher filter is not certified for microplastics reduction.

What Do Brita Pitchers Filter Out?—SimpleLab Tap Score 

Does Berkey Filter Microplastics?

There isn’t a straightforward answer to this. Berkeys are an interesting case because—despite the host of claims touting their near total effectiveness—no one except Berkey really knows what their proprietary filter media (Black Berkey Elements) are made of. We’ve gone into this in more detail in our unbiased in-depth analysis of Berkey filters, but our best guess is that Berkeys contain some combination of activated carbon and ion exchange. Some Berkey dealers, meanwhile, explicitly mention microfiltration.

While we would feel more comfortable knowing the pore size of Berkey’s filtration membrane, many of the contaminants Berkeys appear to be effective at removing (like certain heavy metals and microorganisms) are smaller than microplastics. This would theoretically make Berkeys effective for the removal of microplastics. 

Nevertheless, without any proper certification from the WQA, IAPMO, or NSF/ANSI for the removal of microplastics, we can’t recommend Berkey water filters for your microplastic filtration needs. 

Does Boiling Water Remove Microplastics?

No, boiling water does not remove microplastics. Boiling water is only effective against pathogens and bacteria. It will not eliminate the small plastic particles/polymers that are microplastics. 

A recent study found that boiling hard water (water high in calcium carbonate) may result in the settling out of nano- and micro-plastics that get trapped inside calcium carbonate “incrustants,” which could then be filtered out altogether. While promising, this study has not been validated and we do not recommend this as a treatment strategy because there are many factors impacting its efficiency. 

It’s also important to note that there are a number of contaminants that concentrate when boiled, posing different health risks. If you are considering boiling your water as a microplastic prevention strategy, it's so important to have a clear view of your water's contaminant profile beforehand. If you are boiling water inside of a plastic container, like a plastic kettle or plastic bottle, it is possible that this will release microplastics from the container into your water.

Ultimate and Unbiased Guide to the Best Water Filters for Your Home in 2024—SimpleLab Tap Score

Frequently Asked Questions About Microplastics and Storage Containers

low quality plastic containers

Can Water Filters with Plastic Housing (incl. Pitcher Filters) Leach Microplastics into Drinking Water?

There is no substantial research into water filters or their plastic housing leaching microplastics into drinking water. But, it’s probably a safe bet that microplastic leaching from a durable plastic housing would be insignificant. 

Pitcher filters made of plastic, on the other hand, are often used for years and may degrade over time. Over a long period of time, plastic leaching may occur, but more research into this area is needed to fully understand the risks.

Is it Safe to Use Reusable Water Bottles Made of Plastic? Of Glass?

Theoretically, any product made of plastic can leach microplastics if it’s subjected to regular, repeated use. The quality and type of the bottle’s plastic contributes as well. Certain environmental factors (e.g. temperature, direct sunlight) can also cause physical, chemical, or biological degradation. Even the plastic lid of a water bottle—whether the bottle itself is made of plastic, glass, or aluminum—used at high frequency is liable to contribute to microplastic combination. 

Glass or other non-plastic containers themselves would not contribute to microplastic leaching. But remember, the source of the water you are storing could have microplastics in them.

What About Other Foods and Drinks Stored in Plastic? Can They Contain Microplastics?

Yes, food and drink stored in plastic containers can be contaminated with microplastics if their plastic containers are of low quality (like single-use plastics), repeatedly used, and/or subject to the type of factors that can accelerate degradation. Reheating food in plastic containers, for example, may pose a risk because microplastic leaching is highly temperature-sensitive. 

Another example is plastic baby bottles used for feeding infants—research in one study found that heating and shaking baby bottles contributed to higher microplastics release.

If Microplastics Are Bad, Why Are Filters Made Out of Plastic?

Plastic has long been prized for its low price and versatility. Most products are made from plastic because of plastic’s moldability. However, your specific filtration setup may not be contributing a significant amount of microplastics to your drinking water.

And, as mentioned, studies in this area are ongoing. The best thing you can do is store your plastic pitcher filters and containers away from sunlight, and, if they are subject to a lot of wear and tear, consider replacing them.

What’s the Takeaway?

Microplastics certainly are here, and they are here to stay. But that doesn’t mean they’re worth all of your attention.

  • Microplastics are tiny plastic particles, between one micron (1 μm) and five millimeters (5 mm) in diameter; nanoplastics are plastic particles that have degraded to less than 1 µm. Both the WHO and the CDC have stated there is insufficient evidence linking microplastics to concrete health effects—but potential risks are actively being studied.
  • Microplastics that have entered a water system and made it to your tap cannot be seen, smelled or tasted. The same is true for microplastics in bottled water. The only way to know if microplastics are in your drinking water is to have your water tested by a certified laboratory. There are no at-home testing options (like strips) that can identify the presence of microplastics in a sample of water.
  • Current studies show that microplastics can be removed by household drinking water treatment technologies like reverse osmosis, micro- ultra- and nanofiltration, and certified activated carbon filters. Pore sizes of 2.5 µm or less should effectively filter microplastics from your tap water. You should always ensure the filter has an NSF/ANSI 401 certification.
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About The Author


Sasha Sosnowski is a writer and editor from Los Angeles, California. He studied journalism and history at the University of Warsaw and the University of Arts London and has demonstrated his skills through professional roles as a research assistant, proofreader, magazine editor, and essayist. In his spare time, Sasha enjoys working on his collection of vintage typewriters.
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