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Does Reverse Osmosis Remove Microplastics From Water

Does Reverse Osmosis Remove Microplastics from Drinking Water?

Microplastics have become one of the hottest topics in water quality discussions. Canadian studies have detected tiny plastic particles in bottled water, rain, and even tap water in cities with modern water treatment plants. This is an alarming concern for Canadian homeowners and raises an obvious question: can microplastics be filtered out of water?

For many people, reverse osmosis (RO) is the first solution that comes to mind. But does reverse osmosis remove microplastics effectively, or are there gaps in this technology too? 

RO technology forces water through a semipermeable membrane that removes up to 99% of contaminants from it, including microplastics. Let’s get into the specifics of this topic in this read and help you understand how reverse osmosis eliminates microplastics from water.

Key Takeaways

  • RO removes 90–99% of microplastics ranging from 1 to 100 microns due to their 0.0001-micron membrane pores. Nanoplastics (smaller than 0.1 microns), on the other hand, can occasionally pass through.
  • RO alone isn't enough. Even after filtration, microplastics can seep into your water from membrane shedding, storage tanks, aging plastic tubing, or old PVC pipes in your home's plumbing.
  • System quality and maintenance play an important role in assisting an RO system in effectively filtering microplastics. Premium systems with food-grade plastic and stainless steel components shed fewer microplastic particles. Regular filter changes and membrane inspections keep your RO performing at its best.
  • Use activated carbon post-filters, store water in glass or stainless steel containers, and consider PEX or stainless steel lines to further reduce microplastic contamination in your drinking water

Does RO Remove Microplastics? Quick Answer

Yes, reverse osmosis filters microplastics very effectively from your tap water. The RO technology does a good job at eliminating numerous types of microplastics, particularly those particles that range from 1 to 100 microns in size, but it is not 100% effective in blocking all types of microplastics.

RO systems use a semi-permeable membrane, which works as a physical barrier, blocking out particles larger than the size of its pores. Standard pore size of the RO membrane is 0.0001 microns. Since microplastic particles are bigger than the pores of RO membranes, they get filtered out.

The Dual-Modified RO Membrane for Nanoplastic Removal (2024) study published in Chemosphere confirms that RO membranes are successful in rejecting over 97% nanoplastics, proving that RO technology is reliable in discarding the tiniest of impurities. But some nanoplastics, however, can escape the RO membrane.

What Are Microplastics in Water, and How Do They Originate?

Microplastics are tiny bits of plastic, smaller than 5 mm, and are often invisible to the naked eye.

There are basically two categories of microplastics in terms of their origin: primary and secondary. Primary microplastics are at a tiny size for specific uses, such as industrial abrasives or cosmetic microbeads. Secondary microplastics come from the biological, physical, or chemical breakdown of larger plastic items like bottles, packaging, and bags.

How Do Microplastics Seep into the Canadian Water Supply?

Microplastics make their way into the Canadian water systems from the breakdown of plastic waste in oceans and landfills, synthetic clothing fibers, degradation of plastic items, and industrial waste. 

Let’s give you a brief walkthrough of their journey from their sources into the Canadian water.

  • Every time you wash synthetic clothes such as polyester or fleece jackets, pants, and shirts, teeny fragments of plastic shed from the clothing and travel to the plumbing pipes. They then travel to the wastewater treatment plants. 
  • Whenever it rains, rainwater that runs off the city streets picks up little pieces of plastic, such as those from the litter, tire particles, and industrial waste in the storm drains. Research by the University of Toronto shows that every year, the Don River carries over 500 billion microplastic particles into Lake Ontario, which is the primary source of 90% of the water in the York region.
  • Similarly, different Canadian water sources experience microplastic contamination in different ways. Urban and agricultural runoff carrying polyethylene and polyamide pollutes the Grand River Watershed, which supplies water to the Ontario region. The Fraser River, which is the main water source for British Columbia, accumulates plastics from municipal and industrial wastewater. Discharge from the wastewater treatment plant contaminates the St. Lawrence River, which is a major water source for Quebec. And microplastics from biosolids applied to farms seep into the groundwater wells throughout the Prairies.
  • Water from the main water bodies and sources then travels to the municipal treatment plants across Canada. Treatment systems filter larger contaminants, but the tiniest plastic fragments, particularly those from synthetic textiles and nanoplastics from weathered plastic, can easily slip through the filtration plants. While moving through the plumbing systems, the water may pick up more microplastics from the aging pipes. That explains why Canadian tap water, even in cities with the latest infrastructure, may contain detectable amounts of microplastics.

It is understandable how this information can be upsetting for you, but we are upholding our promise to provide you with an honest picture. The good news is that microplastics can be filtered out of water, and RO systems can help with that.

How Reverse Osmosis Removes Microplastics from Drinking Water

Reverse osmosis works by applying pressure on water that pushes it through a semi-permeable membrane (pore size of 0.0001 microns) that captures particles bigger in size. That’s how it traps microplastics and removes them from drinking water.

To understand how RO removes microplastics, you first need to know how an RO system works as a complete unit and not just the membrane.

How Reverse Osmosis Works?

RO technology works on the principle of applying external pressure to water to reverse its natural direction. Water molecules then flow against their natural gradient, moving from the concentrated side to the purer side. Solutes of contaminants such as bacteria, chemicals, microplastics, PFAS, and other impurities in water separate from it, leaving clean water behind.

The pores of an RO membrane work like a molecular sieve. Activated carbon filters capture particles ranging in size from 0.5 to 1 micron, but RO membranes with a micron size of 0.0001 microns (a hundred times tinier than little microplastic fragments) can trap microscopic particles about a thousand times smaller than a bacterium.

Moreover, a standard multistage RO system adds multiple protective layers before water reaches the membrane.

  • First, a sediment pre-filter traps large particles of debris, including rust and sand.
  • A second layer of activated carbon pre-filter eliminates organic compounds and chlorine that can harm the membrane.
  • Then water moves to the RO membrane that filters out more contaminants.
  • Lastly, a post-filter further refines the water before it reaches the faucet.

This layered mechanism by RO water filtration systems helps them effectively block out microplastics compared to basic carbon filters.

How Effective is RO in Removing Microplastics?

The difference in size of the pores of an RO membrane and the particles of microplastics, and the layered filtration approach, are what make reverse osmosis effective in eliminating microplastics. 

Typically, the size range of microplastics is between 1 and 100 microns. Nanoplastics can go below 0.1 microns in size and present quite a challenge for RO membranes. But reverse osmosis does remove the majority of the microplastics, even most nanoplastics.

Studies show that RO eliminates more than 99% of microplastics of different sizes from the drinking water. A 2019 peer-reviewed study documented that RO filters 99.9% microplastics and nanoplastics from tap water. 

Another 2025 study on desalination plants discovered that RO alone achieves 97.8% to 99.9% microplastic elimination, but remineralization in desalination plants or filter washing in drinking water plants might temporarily reintroduce them, which brings us to our concern discussed below. 

RO Water May Still Have Microplastics

As effective as the RO technology is in eliminating microplastics, RO water may contain them due to the shedding of the membrane, poor plumbing infrastructure, and degradation of the plastic components in the system.

Let’s help you better understand these reasons.

  1. Membrane Material Shedding: In addition, plastic membrane degradation also adds microplastics to the drinking water. With time, chlorine exposure, physical abrasion, and chemical cleaning cause the membrane to wear and tear, which makes it shed tiny polymer pieces into the treated water. This shedding, however, is minimal in well-maintained RO systems.
  2. Degradation of Plastic Components: The RO membrane is one component of the water filter. Once the water leaves the RO membrane, it travels through the other plastic parts in the system, such as tubing, filter housing, and storage tanks, that undergo wear and tear, mixing the plastic shreds in the drinking water. The lower the quality of the plastic, the more shreds you can expect in the water. 
  3. Plumbing Infrastructure: Even if you have a flawless reverse osmosis system, the water still has to flow from the unit to your tap. In most homes, that last stretch runs through older PVC (polyvinyl chloride) pipes. An ‘Accelerated Aging Study on PVC Pipes’ published in ScienceDirect suggests that these pipes can leach microplastics into the water, especially if they have been exposed to pressure fluctuations, extreme chlorination, or high temperatures, or if they are quite old.

While this argument stands strong in its own right, there are two important factors that, if taken care of, can minimize the risk of your RO system delivering water with microplastics.

Importance of System Quality and Maintenance

A high-quality RO system that is properly taken care of won’t really bother you with microplastics in your water.

  • System Quality: Low-quality systems cut corners. Poor-quality plastic naturally sheds more, which ultimately seeps into the water. This is where system quality makes a difference. Premium systems like the Pentair RO system by Illi Water are manufactured using stainless steel, food-grade plastics, high-quality tubing, and storage tanks that cause little to zero shedding. They also come with automatic flush cycles that discard accumulated debris from the membrane, which further reduces the risk of microplastic breakthrough. 
  • Regular Maintenance: Replacing the carbon pre-filters timely, protects the RO membrane from chlorine damage, which is a major cause behind membrane deterioration and shedding. Change the post-filters according to the manufacturer’s guidelines so you can catch any stray microplastic particles before the water reaches your glass. If you do observe a change in taste or a drop in pressure, check the membrane for any physical defects or signs of wear and tear. A properly maintained system not only lasts longer but also consistently delivers cleaner, safer water.

If you are already using a cutting-edge, good-quality RO system that you take excellent care of, your water will stay safe from the harm of microplastics. And if you are concerned about your system’s poor quality, perhaps it’s time to invest in a more reliable system.

There’s another measure that can completely block out microplastics from your water—adding another protective layer.

How to Add Another Layer to Completely Reduce Microplastics from Your Water

Yes, it is the RO membrane doing all the heavy lifting. But a few additional steps can take your water closer to zero microplastic infiltration, such as using post-filters, using glass or stainless steel containers to store water, and choosing safe downstream plumbing pipes.

Here’s how you can implement these measures:

Use Activated Carbon and Other Post-Filters

A high-quality activated carbon post-filter serves as a helpful final polishing stage. It traps any stray microplastic shreds that may have broken from the membrane and found their way into the water. 

Certain advanced units feature ultrafiltration (UF) membranes after the RO stage. UF membranes can have pore sizes as tiny as 0.01 microns, which acts as a solid barrier against microscopic microplastics.

Store Filtered Water in Metal or Glass Containers 

By now, you are well aware of how notorious plastic items are for flaking off microplastics. If you use plastic bottles or containers to store your filtered water, they are likely to release tiny microplastic bits into the water, especially if the containers are scratched, old, or are often exposed to heat.

Switch to glass or stainless steel bottles, containers, and tumblers instead. It eliminates the risk of microplastic contamination. A 2024 Columbia University study discovered that single-use plastic water bottles contain up to 240,000 nanoplastic/liter. The researchers concluded that switching to stainless steel or glass containers is a much safer alternative.

Opt for Safer Downstream Plumbing (PEX or Stainless Steel Lines)

Upgrading your existing plumbing lines or installing brand new ones? Consider changing plastic tubing to stainless steel or PEX (cross-linked polyethylene). PEX is a flexible plastic tubing, primarily used in commercial or residential plumbing.

While research on pipe contamination is still developing, using metal lines for the last lag from your RO system to your faucet eliminates a potential source of infiltration.

Other Benefits of an RO System Beyond Removal of Microplastics

A reverse osmosis system just doesn’t eliminate microplastics from your water. An RO system solves a lot of problems beyond that, including removing 99% of harmful contaminants from the water, improving the water’s taste and odor, and saving costs in the long run. 

Here is what else an RO system brings to your home.

Removes Contaminants Besides Microplastics

An RO membrane physically blocks up to 99% of impurities, including the following: 

  • Heavy metals such as mercury, arsenic, and lead are associated with organ failure and neurological damage. 
  • Total dissolved solids (TDS) comprise inorganic and organic compounds in your water, linked to neurological harm, increased cancer risk, and kidney damage. 
  • Pathogens like Cryptosporidium, Giardia, and E. coli that can cause digestive problems.

Improves Taste and Odor

Municipal water treatment doesn’t tackle chlorine and chloramines, which are otherwise safe for consumption but add an unpleasant taste and odor to the water.

RO systems employ activated carbon pre-filters to completely slash these chemicals before water reaches the membrane. The result? Cleaner, fresher, and tastier water that doesn’t taste like swimming pool. Not only will you enjoy drinking it more, but your coffees, teas, pastas, soups, and other meals will taste more delicious too. This should also answer your query on: Will reverse osmosis remove chlorine?

Ensures Good Health and Safety

While municipally treated water is safe to drink, it can pick up contaminants when it moves from the treatment plant to your faucet. RO tackles all the impurities that may have leached into the water due to exposure to harmful chemicals, industrial byproducts, and agricultural runoff that standard treatment falls short of removing. 

For families with little children, elderly members, or members with a compromised immune system, this extra layer of protection makes a whole lot of difference.

Flexible Installation and Easy Access to Clean Water

RO systems easily fit most homes. They are easy to install and are designed keeping in mind the architecture of modern kitchens. 

  • Under-sink units sit neatly under the kitchen cabinet and deliver water through a dedicated faucet.
  • Countertop models are ideal for renters and those with small spaces, as they don’t need any plumbing modifications. 
  • Whole-house systems treat water at every tap, appliance, and shower. 

Irrespective of which system you choose, you enjoy the convenience of getting water on demand without waiting for the jugs to fill or the store to open for bottled water.

Save Cost in the Long Term and the Environment

Bottled water is costly. A Canadian family of four using bottled water roughly spends around $720 to $1,200+ on single-use plastic bottles. An RO system, on the contrary, costs less and pays for itself within months. 

RO systems aren’t only cost-effective but also eco-friendly, as they eliminate your reliance on plastic bottled water, which translates into a lower carbon footprint.

Frequently Asked Questions

What is the best filter to remove microplastics from water?

Reverse osmosis systems are the most powerful and effective when it comes to microplastic removal. A high-quality RO membrane removes 90% to 99% of microplastic particles, including shreds as tiny as 0.1 microns. Add a carbon post-filter to the RO system, and you’ll get an extra layer of protection.

Are there DIY solutions for microplastic removal?

No, there aren’t any DIY solutions to remove microplastics from drinking water. Sediment settling and boiling the water don’t filter microplastics. Faucet attachments and basic filter pitchers cannot eliminate microplastics as well. A cutting-edge RO system is the best available solution to address this concern. 

Does all water have microplastics?

Based on multiple European and North American studies, most tap, bottled, and even rainwater contain detectable levels of microplastics. The concentration of microplastics varies by water source, location, and treatment methods. 

Do microplastics disappear forever after RO filtration?

No. RO systems filter out microplastics and flush them out in the concentrated wastewater. That wastewater flows to the sewer and is likely to make its way to a treatment plant. And that’s how certain amounts of microplastics may still enter the environment. However, RO does filter microplastics from your drinking water.

Is distillation better than RO for removing microplastics?

Distillation effectively removes microplastics since plastic particles cannot vaporize with water. But distillation consumes more energy and time and produces less water per day than RO. For most Canadian homeowners, RO is the more practical and cost-effective choice for daily use.

The Bottom Line: Does RO Filter Microplastics?

Microplastics find their way into every form of water, including the municipally treated Canadian tap water. But if you use an advanced RO system, you’ll stay safe against them because reverse osmosis does filter out 90% to 99% of microplastics, while also cutting out other dangerous contaminants such as heavy metals and bacteria.

Yes, RO systems aren’t perfect, and certain nanoplastics may still leach into the water, but the levels are barely measurable. And if yours is a premium system, and you maintain it properly, it will do an impeccable job at stripping maximum microplastics from the drinking water.

Want to upgrade your existing system to a more advanced, powerful, and comprehensive RO system? Explore Illi Water’s brilliant range of reverse osmosis systems, specifically designed for Canadian homes and water challenges.

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