What if I told you that 93% of bottled water tested in a global study contained microplastics?1 That’s not a scare tactic, it’s what researchers from the State University of New York found when they tested 259 bottled water samples from 11 brands across nine countries.2 Even more shocking? Their earlier research on tap water also showed widespread contamination, with microplastics detected in the vast majority of samples worldwide.
Microplastics have quietly infiltrated our water supply, appearing in both tap water and bottled water. With growing concerns about these microscopic plastic particles and their potential health impacts, many people are asking a crucial question: Does reverse osmosis remove microplastics?
This guide breaks down how reverse osmosis works, how effective it is against microplastics, and what makes microplastics a concern in the first place. You’ll also find practical tips to help reduce your exposure in daily life.
What Are Microplastics?
Before we tackle whether reverse osmosis can remove these tiny invaders, let’s clarify what we’re dealing with. Microplastics are precisely what they sound like: microscopic pieces of plastic that measure less than 5 millimeters in length. To put that in perspective, that’s smaller than a grain of rice, which typically measures 6-7 millimeters.
There are Two Main Categories
- Primary microplastics are intentionally manufactured to be tiny. Beyond synthetic fibers from polyester clothing, some personal care and cleaning products still contain plastic microbeads today. These include certain types of makeup (like glittery mascaras or face powders) and cleaning products that rely on abrasive microplastics for scrubbing power.
- Secondary microplastics are the result of larger plastic items breaking down over time. That water bottle you tossed aside, the plastic bag that escaped into the environment, or the fishing net lost at sea, all eventually fragment into countless tiny pieces through exposure to sunlight, waves, and weather.
One of the sneaky aspects of microplastics is their infiltration of our water systems. They enter through multiple pathways: runoff from roads (including tire wear particles), industrial discharge, wastewater treatment plants that struggle to capture such tiny particles, and the gradual breakdown of plastic waste in the environment.
Even bottled water isn’t safe—studies have found microplastics in both single-use bottles and larger containers, likely from the plastic packaging itself or contamination during the bottling process. And yes, glass bottles can contain microplastics due to the caps used.
What makes this particularly concerning is that microplastics are persistent. Unlike organic matter that biodegrades, these plastic fragments can stick around for hundreds of years, accumulating in our water sources and working their way up the food chain.
Related Article: Microplastics in Cosmetics: A Complete Guide to Hidden Beauty Industry Pollutants
Can Reverse Osmosis Remove Microplastics?
Yes, and here’s why: the filter in a reverse osmosis system has incredibly tiny pores that are so small that even the smallest microplastic particles can’t get through. Most microplastics are far too large to pass the membrane, which acts like an ultra-fine screen.
Research shows that reverse osmosis systems can remove over 99% of microplastics when they’re working properly. In some cases, they’ve been shown to block 99.9% of larger plastic particles. That makes RO one of the most reliable ways to keep microplastics out of your tap water.
Health Concerns and Prevalence of Microplastics in Water
Here’s where it gets unsettling: microplastics have been found in blood, lung tissue, placental tissue, and even breast milk. A groundbreaking study led by microplastics scientist Heather Leslie found microplastics in the blood of 17 out of 22 healthy adults, providing clear evidence that these particles can enter our bloodstream.3
Even more concerning, when microplastics break down into nanoplastics, they may be able to cross biological barriers like the intestinal lining, placenta, and blood–brain barrier, potentially entering and accumulating in sensitive tissues.
The health implications are still being studied, but early research suggests several potential concerns. Microplastics may trigger inflammatory responses in the body. Because they can carry harmful chemicals on their surfaces, such as pesticides, heavy metals, and other toxins, they may act as tiny delivery vehicles for these substances. Some studies suggest possible links to hormonal disruption, though more research is needed to understand the long-term effects.
What we do know for sure is just how widespread this contamination has become. Studies have found microplastics in 93% of bottled water4 samples and 92% of tap water5 samples worldwide. That’s not a typo; we’re talking about nearly universal contamination of our drinking water sources.
The concentration varies by location and source, but the fact remains: microplastics have become an unavoidable part of our modern water supply. This isn’t about fear-mongering; it’s about acknowledging a reality that affects us all and taking practical steps to minimize our exposure.
Organizations like the World Health Organization continue to study the health implications. Still, even they acknowledge that while the current health risk from microplastics in drinking water appears to be low based on available evidence, the lack of reliable data and the constant exposure raise legitimate concerns about long-term effects.
How Reverse Osmosis Works
Think of reverse osmosis as nature’s most selective bouncer; it only lets the tiniest, most desirable molecules through while blocking everything else. The technology works by forcing water through an incredibly fine membrane under pressure, creating some of the purest water possible.
The magic happens at the molecular level. RO membranes have pores that are approximately 0.0001 microns in size. To put this in perspective, a human hair is approximately 50-100 microns wide, bacteria range from 0.2 to 2 microns, and most viruses are 0.02 to 0.3 microns. The RO membrane’s pores are so tiny that only water molecules (which are approximately 0.00028 microns in diameter) can pass through easily.
A Quality Reverse Osmosis System Typically Works in 4 Stages
This multi-stage approach ensures that water emerges not only free from microplastics but also from a wide range of other contaminants that may be lurking in your water supply.
- Pre-filtration removes larger particles, sediment, and chlorine that could damage the delicate RO membrane. This usually involves a sediment filter and a carbon filter.
- The RO membrane is where the actual work takes place. Water molecules pass through while contaminants, including microplastics, dissolved salts, heavy metals, bacteria, and viruses, are rejected and flushed away.
- Post-filtration often includes a final carbon filter to polish the taste and remove any residual odors.
- Optional remineralization adds back beneficial minerals that were removed during the RO process, since pure RO water can taste a bit flat.
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Best Reverse Osmosis Systems
Your fridge filter might not be doing as much as you think! This guide breaks down the best reverse osmosis systems that remove contaminants like PFAS and microplastics, plus they pay for themselves in under a year compared to the costs of bottled water.
Comparison with Other Filtration Methods
While RO leads the pack in microplastic removal, understanding how different filtration technologies compare can help you make the best choice for your specific situation. Here’s how the most common home filtration options compare:
Pitcher and Refrigerator Filters
Pitcher and Refrigerator Filters are the most popular starting point for many households, but they’re designed primarily for chlorine removal and taste improvement. Their activated carbon filters have pore sizes that are simply too large to effectively catch microplastics. Think of trying to catch rice grains with a basketball hoop—it’s just not going to work.
Faucet-Mounted and Under-Sink Carbon Filters
Faucet-Mounted and Under-Sink Carbon Filters offer slightly better performance due to more advanced carbon filtration, but they’re still not designed with microplastics in mind. They might catch some of the larger plastic particles, but the majority will pass right through.
Reverse Osmosis Systems
Reverse Osmosis Systems stand alone in their ability to remove microplastics from drinking water effectively. The membrane’s pores physically block these particles, making RO the only widely available home filtration technology that consistently delivers 99%+ removal of microplastics.
Cost-Benefit Reality Check
While the upfront cost of an RO system might seem steep compared to a $30 pitcher filter, consider what you’re getting. If you’re currently buying bottled water (which studies show contains microplastics anyway), an RO system typically pays for itself within one to two years while providing superior protection.
For households serious about reducing microplastics, the choice often comes down to this: invest in a proven solution that works, or settle for cheaper options that offer minimal protection against the contaminants you’re trying to avoid.
It’s worth noting that while RO excels at removing microplastics, there are some limitations to consider. The smallest particles, sometimes referred to as nanoplastics, that are smaller than 0.1 microns may occasionally pass through, although these represent a tiny fraction of plastic pollution. Additionally, RO systems require regular maintenance to maintain their effectiveness, including filter changes and membrane replacement.
Do RO Systems Remove Other Emerging Contaminants Besides Microplastics?
Absolutely! RO systems are excellent at removing a wide range of emerging contaminants that concern health experts, including:
- Heavy metals: Lead, arsenic, mercury, chromium
- Chemical contaminants: PFAS (forever chemicals), pharmaceuticals, pesticides
- Disinfection byproducts: Chlorine compounds, trihalomethanes
- Minerals: Iron, manganese (which can affect taste and appearance)
- Biological contaminants: Bacteria, viruses, parasites
This comprehensive removal is why RO is often considered the gold standard for home water treatment.
More Reasons to Choose Reverse Osmosis
Microplastic removal might be the reason you started looking into reverse osmosis, but the advantages go well beyond that. RO systems are powerful filtration tools that can dramatically improve your water quality across the board.
- Thorough Contaminant Removal: RO systems filter out more than just microplastics. They also remove dissolved salts, heavy metals like lead and mercury, nitrates, fluoride, bacteria, viruses, and a wide range of chemical pollutants. If you’re concerned about what’s in your tap water, this gives you a clean slate.
- Better Taste and Odor: Chlorine, total dissolved solids, and other compounds that affect flavor are all filtered out. The result is clean, neutral-tasting water that’s ideal for drinking and cooking.
- Less Plastic Waste: If you currently rely on bottled water, switching to an RO system can dramatically cut your plastic use. One system can replace hundreds or even thousands of bottles per year. While RO systems do produce some wastewater, the overall environmental impact is much lower than that of bottled water.
- Long-Term Cost Savings: Although there’s an upfront cost, the per-gallon price of RO water is significantly lower than that of bottled water. Over time, especially for households that consume a lot of water, the savings add up.
- Convenient Access to Clean Water: No more lugging cases of bottled water from the store or worrying about running out. RO systems provide clean, filtered water directly from your tap any time you need it.
- Simple Maintenance: Most systems are easy to maintain. Filters typically need to be changed every 6 to 12 months, and membranes last around 2 to 3 years, depending on your water usage and local water quality.
6 Additional Ways to Reduce Your Microplastic Exposure
- Skip Single-Use Plastics Whenever You Can – Reusable choices matter more than ever. Stainless steel or glass water bottles, beeswax wraps, cloth produce bags, and metal lunchboxes all reduce your reliance on plastics that eventually break down into microplastic fragments. If it’s plastic and disposable, there’s usually a longer-lasting option.
- Upgrade How You Store and Heat Food – Microwaving plastic containers, even the “microwave-safe” kind, can cause plastic particles to migrate into your food. Stick with glass or ceramic containers for storage and reheating. When ordering takeout, transfer food to a non-plastic dish before eating, and say no to plastic cutlery when possible.
- Buy Fresh, Not Packaged – The more processed or packaged a food item is, the more likely it is to come into contact with plastic during its production and distribution. Prioritize unpackaged produce, bulk-bin staples, and fresh foods stored in paper or glass. Farmers’ markets are often a great place to start.
- Choose Clothes That Don’t Use Plastic – Polyester, nylon, acrylic, and other synthetic fabrics release thousands of microfibers every time they’re washed. Over time, those fibers end up in rivers, oceans, and household dust. Opt for clothing made from natural materials like organic cotton, linen, wool, or hemp. They breathe better and biodegrade safely.
- Stop Microfibers at the Source – If you already own synthetic clothes (most of us do), consider using a Guppyfriend bag or installing a microfiber filter like PlanetCare or Lint LUV-R on your washing machine. These solutions trap microfibers before they enter the wastewater stream, keeping them out of oceans and soils.
- Support Plastic-Free Innovation and Local Action – Look for brands that are transparent about their packaging and offer plastic-free or compostable alternatives. You can also amplify your impact by joining cleanups, writing to local officials, or supporting legislation aimed at reducing plastic waste. Groups like Beyond Plastics and the Plastic Pollution Coalition are excellent starting points.
Related Article: How to Avoid Microplastics: 15 Practical Ways to Reduce Exposure
Frequently Asked Questions about Microplastics and Filtration
How do wastewater treatment plants handle microplastics?
Most conventional wastewater treatment plants weren’t designed to target microplastics, especially particles smaller than 100 microns.
While primary treatments like screening and settling remove larger debris, smaller microplastics often require advanced filtration or membrane technologies to be effectively captured. Although many microplastics are retained in sludge, some still escape into effluent, raising concerns about long-term environmental exposure.
How can I tell if the RO system is third-party certified?
Look for certifications from reputable organizations, such as NSF International or the Water Quality Association (WQA). Third-party certified systems have undergone independent testing to verify their performance claims. Check for:
- NSF/ANSI Standard 58: Tests RO systems for contaminant reduction
- NSF/ANSI Standard 42: Tests for chlorine and taste/odor reduction
- NSF/ANSI Standard 53: Tests for health-related contaminant reduction
- WQA Gold Seal: Indicates the product meets industry standards
Check out our article on our top picks for certified reverse osmosis systems.
This Has Been About: Does Reverse Osmosis Remove Microplastics?
While the long-term health effects of microplastic consumption are still being studied, the widespread contamination of our water supply is an undeniable reality. With microplastics found in over 90% of both tap and bottled water samples worldwide, taking proactive steps to reduce your exposure makes sense from both a health and peace-of-mind perspective.
If you’re concerned about microplastics in your drinking water, reverse osmosis provides a proven and practical solution. Beyond just removing plastic particles, RO systems offer comprehensive water treatment that addresses a wide range of contaminants, delivering great-tasting water directly from your tap.
View Article Sources
- Mason, S. A., Welch, V. G., & Neratko, J. (2018). Synthetic polymer contamination in bottled water. Frontiers in Chemistry, 6, Article 407. https://doi.org/10.3389/fchem.2018.00407
- Mason, S. A., Welch, V. G., & Neratko, J. (2018). Synthetic polymer contamination in bottled water. Frontiers in Chemistry, 6, Article 407. https://doi.org/10.3389/fchem.2018.00407
- Pinto-Rodrigues, A. (2023, March 24). Microplastics are in our bodies. Here’s why we don’t know the health risks. Science News. https://www.sciencenews.org/article/microplastics-human-bodies-health-risks
- Mason, S. A., Welch, V. G., & Neratko, J. (2018). Synthetic polymer contamination in bottled water. Frontiers in Chemistry, 6, Article 407. https://doi.org/10.3389/fchem.2018.00407
- Kosuth, M., Wattenberg, E. V., & Mason, S. A. (2018). Anthropogenic contamination of tap water, beer, and sea salt. PLOS ONE, 13(4), e0194970. https://doi.org/10.1371/journal.pone.0194970
Feature image from Amazon.
