How to Remove Nanoplastics from Drinking Water

You've probably heard about microplastics in drinking water by now. But there's a smaller, more concerning category of plastic contamination that most people haven't heard of: nanoplastics.

Nanoplastics are not just smaller versions of microplastics. They behave fundamentally differently inside the body. While microplastics mostly pass through your digestive system, nanoplastics are small enough to cross cell membranes, enter your bloodstream, and accumulate in your organs. A growing body of research suggests they can reach the brain, the liver, the lungs, and even the placenta.

A landmark 2024 study found roughly 240,000 nanoplastic particles per liter of bottled water. That's 10 to 100 times more contamination than previous estimates that only measured microplastics. The science on nanoplastics is advancing rapidly, and the picture is unsettling.

The good news: the right filtration system can remove nanoplastics from your drinking water. But the filter that handles microplastics might not be enough. This guide covers exactly what works, what doesn't, and how to protect your household based on the latest evidence.

What Are Nanoplastics?

The term "nanoplastics" refers to plastic particles smaller than 1 micron (1,000 nanometers) in any dimension. To put that in perspective:

• Microplastics range from 1 micron to 5 millimeters. You can sometimes see the larger ones with the naked eye.
• Nanoplastics are smaller than 1 micron. They are completely invisible, even under a standard optical microscope. Detecting them requires advanced techniques like Raman spectroscopy or stimulated Raman scattering (SRS) microscopy.
• A human red blood cell is about 7 microns wide. Nanoplastics are smaller than your blood cells.
• A strand of human hair is roughly 70 microns. You would need to line up at least 70 nanoplastic particles to span the width of a single hair.

Why nanoplastics matter more than microplastics

Size is everything when it comes to biological impact. Microplastics (particles larger than 1 micron) are concerning, but your body handles them relatively well. Most pass through the digestive tract and are excreted. Nanoplastics are a different story entirely.

Because they are small enough to cross biological barriers, nanoplastics can:

• Enter the bloodstream through the gut lining. A 2022 study in Environment International detected nanoplastic particles in human blood for the first time, finding them in 77% of samples tested.
• Cross the blood-brain barrier. Animal studies have shown polystyrene nanoplastics accumulating in brain tissue after oral exposure, raising questions about potential neurotoxic effects.
• Penetrate the placenta. Research published in Environment International (2023) found nanoplastic particles in human placental tissue, meaning exposure begins before birth.
• Accumulate in organs. Unlike microplastics that mostly transit through the gut, nanoplastics have been detected in the liver, kidneys, lungs, and heart tissue.
• Carry more surface chemicals per unit of mass. Smaller particles have a higher surface area to volume ratio, meaning they carry proportionally more adsorbed pollutants like heavy metals, pesticides, and endocrine disruptors into your body.

How Many Nanoplastics Are in Your Water?

Until recently, scientists could only measure microplastics in water. Nanoplastics were too small to detect with existing methods. That changed in 2024 when researchers at Columbia University and Rutgers University developed a new technique using stimulated Raman scattering (SRS) microscopy to identify and count nanoplastic particles for the first time.

The 2024 Columbia/Rutgers study

Published in the Proceedings of the National Academy of Sciences (PNAS) in January 2024, the study by Naidu et al. tested three popular brands of bottled water and found approximately 240,000 nanoplastic particles per liter. That's 10 to 100 times more plastic contamination than previous estimates that could only detect microplastics.

The particles came primarily from two sources:

• PET (polyethylene terephthalate), the plastic the bottles are made from. Every time a bottle is squeezed, opened, or exposed to heat, tiny fragments break off into the water.
• Polyamide (nylon), likely shed from the plastic filtration membranes used during the bottling process itself. In other words, the industrial filters used to "purify" bottled water may actually be introducing nanoplastics.

The researchers noted that nanoplastics made up roughly 90% of all plastic particles found. Previous studies that only counted microplastics were seeing just the tip of the iceberg.

Tap water vs. bottled water

While comprehensive nanoplastic data for tap water is still emerging, the available evidence consistently points in the same direction: bottled water contains significantly more nanoplastics than tap water.

The primary reason is the container itself. PET plastic bottles continuously shed nanoscale fragments into the water they hold, especially when exposed to heat, sunlight, or physical stress. Tap water, while it does pick up nanoplastics from treatment processes and distribution pipes, doesn't sit in a plastic container for weeks or months before you drink it.

A 2022 study in the Journal of Hazardous Materials tested both tap and bottled water sources and found nanoplastic concentrations in bottled water that were several times higher than tap water from the same region. The temperature history of the bottle matters enormously. Water that has been stored in warm conditions (a warehouse in summer, a delivery truck, your car) will contain substantially more nanoplastics than water that has been kept cool.

Why Most Filters Miss Nanoplastics

If you already own a water filter, you might assume you're covered. For microplastics, you might be right. For nanoplastics, probably not.

The core issue is pore size. Every filter works by forcing water through a medium that blocks contaminants above a certain size. If the contaminant is smaller than the pore, it passes right through.

Where common filters fall short

• Granular activated carbon (GAC) filters, including standard Brita and PUR pitchers, have inconsistent pore structures. They primarily work through adsorption (contaminants sticking to the carbon surface) rather than physical size exclusion. They were never designed to catch particles below 5 to 10 microns, let alone nanoplastics at 0.001 to 1 micron.
• Basic carbon block filters have tighter pores than GAC, typically rated at 0.5 to 2 microns. They catch some of the larger nanoplastics through a combination of size exclusion and adsorption, but particles smaller than the rated pore size pass through.
• Ultrafiltration (UF) membranes have pores around 0.01 to 0.1 microns. They handle most microplastics effectively and catch a portion of the larger nanoplastics, but the smallest nanoplastics (under 100 nanometers) can still slip through.
• Refrigerator filters and faucet attachments are typically basic GAC filters in a compact housing. They improve taste by reducing chlorine but have minimal effectiveness against any plastic particles, let alone nanoplastics.

The key takeaway: a filter that removes 90% of microplastics might remove far less than 50% of nanoplastics, because the smaller particles pass right through gaps in the filtration media. You need a filter specifically capable of blocking particles at the nanometer scale.

The Best Filtration Methods for Nanoplastics

Based on current research and filtration science, here are the methods that actually work against nanoplastics, ranked from most to least effective.

1. Reverse osmosis (the gold standard)

Reverse osmosis (RO) forces water through a semipermeable membrane with pores approximately 0.0001 microns in diameter. That's 10,000 times smaller than the threshold for nanoplastics (1 micron) and roughly 10 times smaller than the smallest nanoplastics scientists have measured in water.

RO is the most reliable method for nanoplastic removal because it doesn't rely on the particles "sticking" to a filter medium. It physically blocks them. The membrane acts as an absolute barrier. If the particle is bigger than 0.0001 microns, it doesn't pass through. Period.

Beyond nanoplastics, RO also removes:

• 95 to 99% of PFAS ("forever chemicals")
• 95 to 99% of heavy metals (lead, arsenic, mercury)
• 90 to 99% of chlorine and chloramine
• Pharmaceutical residues, pesticides, and VOCs
• Virtually all bacteria and viruses

Downsides of RO: It produces wastewater (older systems waste 3 to 4 gallons for every gallon filtered, though newer tankless systems are more efficient at around 2:1 or better). It also removes beneficial minerals, so you may want a system with remineralization or add mineral drops to your water.

2. Nanofiltration

Nanofiltration (NF) membranes have slightly larger pores than RO, typically around 0.001 microns. That's still far smaller than nanoplastics, making NF highly effective for this purpose. NF membranes remove the vast majority of nanoplastic particles while producing less wastewater than RO and retaining more beneficial minerals in the water.

NF is less commonly available as a consumer product compared to RO, but some advanced under-sink systems incorporate nanofiltration membranes. If you find a system marketed as "nanofiltration," it will handle nanoplastics effectively.

3. Advanced carbon block filters (with caveats)

High quality carbon block filters with sub-micron ratings (0.5 microns or less) can capture some nanoplastics through two mechanisms: physical size exclusion for larger nanoplastics and adsorption for smaller ones. Carbon is excellent at adsorbing organic compounds, and some nanoplastic particles will stick to the carbon surface as water passes through.

However, carbon block filters are less reliable and less consistent for nanoplastics than RO or NF. Their effectiveness depends on the specific pore size, the water flow rate (slower is better for adsorption), and how fresh the filter is. As a carbon block filter ages and its adsorption capacity decreases, nanoplastic removal drops significantly.

Advanced carbon block filters are a meaningful step up from no filtration, especially for budget conscious households, but they should not be considered equivalent to reverse osmosis for nanoplastic removal.

Note: Nanoplastic removal rates are estimates based on pore size comparisons and available research. Standardized testing protocols for nanoplastic removal in consumer filters do not yet exist. RO and NF ratings are based on membrane physics. Carbon block and other ratings are approximations.

Recommended Filters

Based on filtration science and the specific challenge of nanoplastics, here are the systems we recommend. Reverse osmosis systems are listed first because they offer the most reliable nanoplastic removal.

Under-sink reverse osmosis (best protection)

• APEC ROES-50 ($180 to $200). Five stage filtration, NSF certified, and one of the most trusted RO systems available. The RO membrane (0.0001 micron pores) blocks essentially all nanoplastics. Produces about 50 gallons per day. The best value for most households. Installation takes about an hour if you're comfortable with basic plumbing.
• Waterdrop G3P800 ($350 to $400). Tankless design with a fast 800 gallon per day flow rate and a more efficient 3:1 pure to drain water ratio. Smart display shows filter life in real time. The premium option for households that want faster flow and less water waste. Also NSF 58 certified.

Countertop reverse osmosis (no installation)

• AquaTru ($350 to $450). Countertop RO that requires zero plumbing modifications. Fill the tank, press a button, and filtered water collects in the reservoir. NSF certified to remove 83 contaminants. Excellent for renters or anyone who doesn't want to modify their kitchen plumbing. The four stage filtration includes an RO membrane that handles nanoplastics with the same effectiveness as under-sink systems.

Advanced carbon block (budget option)

• Clearly Filtered Pitcher ($80 to $90). Uses proprietary affinity filtration media that goes beyond standard carbon block technology. Independently tested to remove over 365 contaminants including PFAS (98%+) and microplastics (up to 99.5%). While Clearly Filtered has not published specific nanoplastic testing data, the combination of sub-micron filtration and chemical adsorption should capture a meaningful portion of nanoplastics. This is the best budget starting point if RO is out of reach right now, though it should not be considered equivalent to RO for the smallest nanoplastic particles.

What About Boiling?

For microplastics, boiling does nothing. In fact, it can concentrate particles by reducing water volume. But a 2024 study on nanoplastics tells a more nuanced and surprisingly hopeful story.

A study by Zhanjun Li and colleagues, published in Environmental Science & Technology Letters in early 2024, found that boiling tap water for five minutes can remove up to 80 to 90% of nanoplastics, but only under specific conditions.

How it works

When hard water (water with high mineral content, particularly calcium) is boiled, calcium carbonate precipitates out of solution and forms solid particles. These particles effectively encapsulate nanoplastics as they form, trapping the tiny plastic particles inside mineral clusters. The clusters are large enough to be removed by pouring the water through a simple coffee filter or fine mesh strainer.

The researchers tested water samples with varying hardness levels and found:

• Hard water (above 120 mg/L calcium carbonate): up to 80 to 90% nanoplastic removal after boiling and filtering
• Soft water (below 60 mg/L calcium carbonate): significantly less effective, as there isn't enough mineral content to form the encapsulating precipitate

Practical implications

Boiling is not a replacement for a proper filtration system, but it's a useful piece of knowledge in specific situations:

• If you have hard water and no filter yet, boiling your drinking water for five minutes and then pouring it through a paper coffee filter is a free, immediate step you can take today.
• If you're traveling and don't have access to your home filtration system, boiling and filtering with a coffee filter is a practical backup, assuming the local water is relatively hard.
• If you have soft water, the effect is much weaker. Adding a small amount of calcium (like food grade calcium carbonate powder) to soft water before boiling may improve effectiveness, though this hasn't been extensively studied.

Storage Matters

Filtering nanoplastics out of your water only helps if you don't reintroduce them through plastic storage containers. This step is especially important for nanoplastics because the very act of storing water in plastic generates new nanoplastic particles over time.

Glass is the best option

Glass is chemically inert. It does not shed particles, does not leach chemicals, and does not react with water regardless of temperature or storage duration. Once you've filtered your water, transferring it to a glass pitcher or glass bottle keeps it clean.

Borosilicate glass (like Pyrex) is more durable and temperature resistant than standard soda lime glass. A borosilicate glass pitcher in the fridge is the ideal way to store filtered water.

Stainless steel for portability

For water on the go, food grade stainless steel (18/8 or 304 grade) is the next best choice. It's durable, doesn't leach, and keeps water cold if insulated. Avoid bottles with painted or coated interiors, as some internal coatings may contain plastics.

Why plastic storage undermines your filter

If you filter your water through an RO system and then pour it into a plastic pitcher or plastic water bottle, you're undoing some of your work. Plastic containers continuously release nanoplastic particles into the water they hold. The rate increases with:

• Temperature. Warm storage accelerates particle shedding dramatically. Never leave any plastic water container in a car, near a window, or anywhere warm.
• Time. The longer water sits in plastic, the more particles accumulate. Water that has sat in a plastic bottle for months (common for store bought bottled water) contains far more nanoplastics than freshly filled water.
• Physical stress. Squeezing, dropping, or crushing a plastic bottle causes micro fractures in the plastic that release additional particles.
• UV exposure. Sunlight breaks down plastic polymer chains, accelerating fragmentation at the nanoscale.

Quick Action Plan

If you want to reduce nanoplastic exposure from water, here are the steps in order of priority:

1. Stop buying water in plastic bottles immediately. Bottled water is the single largest source of nanoplastic exposure from water. This step alone could eliminate hundreds of thousands of nanoplastic particles from your daily intake.
2. Get a glass or stainless steel water bottle for daily use. Fill it from your tap for now if you don't have a filter yet. Unfiltered tap water is still better than plastic bottled water for nanoplastic exposure.
3. If you have hard water and no filter, start boiling your drinking water for five minutes and pouring it through a paper coffee filter. This is free and can reduce nanoplastics by up to 80 to 90%.
4. Invest in a reverse osmosis system. An APEC ROES-50 under-sink system (~$190) or an AquaTru countertop system (~$400) provides the most comprehensive protection available.
5. If RO is beyond your budget right now, get a Clearly Filtered pitcher (~$80) as an interim step. It won't match RO for nanoplastics, but it's vastly better than no filtration.
6. Use filtered water for cooking too. Boiling unfiltered water for pasta, rice, or soup concentrates contaminants. Use your filtered water for everything you consume.
7. Store filtered water in glass, never plastic. A glass pitcher in the fridge keeps your filtered water clean until you drink it.
8. Set filter replacement reminders. An old, saturated filter loses effectiveness. Follow the manufacturer's replacement schedule.

The Bottom Line

Nanoplastics represent a more serious concern than microplastics because of their ability to cross biological barriers and accumulate in organs. The research is still in its early stages, but what we know so far is enough to justify taking action.

The most impactful steps are straightforward. Stop drinking from plastic bottles. Filter your tap water with a reverse osmosis system. Store the filtered water in glass. These three changes eliminate the vast majority of nanoplastic exposure from water.

You don't need a perfect solution to make a meaningful difference. Switching from bottled water to filtered tap water could reduce your daily nanoplastic intake by hundreds of thousands of particles. Adding an RO filter takes it close to zero. That's a massive improvement, and it's achievable on a reasonable budget.

Water is one piece of the puzzle. If you're working on reducing plastic exposure more broadly, our step by step guide to reducing plastic exposure helps you prioritize the changes that make the biggest difference across all sources, not just water.

Frequently Asked Questions