Microplastics in drinking water are tiny plastic particles that have been found in tap water, bottled water, and even well water around the world, usually in very small amounts. They come from many everyday sources and can vary greatly in size, with some being too small to see. Scientists are still studying their possible health effects, but there are reliable ways to lower microplastics in drinking water, including using certain water filters and making a few simple changes in daily habits.
What Are Microplastics in Drinking Water?
Microplastics in drinking water are small pieces of plastic that are about 1 micrometre to 5 millimetres in size. Nanoplastics are even smaller and measure less than 1 micrometre. Just for comparison, a human hair is about 70 micrometres wide. Many microplastics found in drinking water are much smaller than that. California, the first place to create an official definition for drinking water testing, defines microplastics as solid polymer particles that are insoluble in water. These tiny particles have been found in tap water, bottled water, groundwater, and other drinking water supplies around the world.
What Size Are Microplastics in Drinking Water?
The size of microplastics in drinking water ranges from less than 1 micrometre to 5 millimetres, but most of them are very small, often under 10 micrometres. A 2024 bottled water study found that about 90% of the particles were nanoplastics smaller than 1 micrometre. These particles are so tiny that thousands of them could fit across the width of a single human hair. Size matters because smaller particles are harder to filter out of water. Scientists are also studying whether these tiny particles are more easily absorbed by the body than larger pieces of plastic.
Are Microplastics Really in Tap and Bottled Water?
Yes. Microplastics have been found in drinking water around the world, including tap water, bottled water, well water, groundwater, and even rainwater. Scientists have found different amounts of microplastic pollution in drinking water depending on the country, the water source, and the testing method used. There is still no single worldwide testing standard, so the numbers vary widely between studies.
The following table shows typical Microplastic Counts by Water Type:
| Water Type | Typical Particle Count | Study |
| Tap Water | A few to several dozen particles per litre | Orb Media Global Study (2017) |
| Bottled Water | About 240,000 particles per litre | Columbia and Rutgers Study (2024) |
Are There Microplastics in Tap Water?
Yes, there are microplastics in tap water. The 2017 Orb Media investigation found microplastics in tap water samples collected from many countries, including the US, UK, and several other nations. Most studies report that tap water has microplastics ranging from a few particles to a few dozen particles per litre. The exact amount of microplastics in tap water depends on where you live, the source of the water, and the way the study was performed. Because scientists do not yet use one standard testing method, results can differ from one study to another. Even so, the research clearly shows that microplastics in tap water are common and are found in drinking water around the world.
How Much Microplastic Is in Bottled Water?
A 2024 bottled water microplastic study found an average of about 240,000 plastic particles in one litre of bottled water. Researchers from Columbia University and Rutgers University also found that 90% of these particles were nanoplastics smaller than 1 micrometre. This was 10 to 100 times higher than earlier estimates. Scientists believe that this plastic comes from the bottle itself, the cap, and even the filtration and bottling process. Common types included PET plastic and nylon. These findings do not mean that bottled water is dangerous. Researchers are still studying the health effects of these tiny particles.
Does Well Water Have Microplastics?
Yes. Studies have found microplastics in groundwater and well water, although there has been less research on well water than on tap water and bottled water.
Because private wells are not treated by a public water utility, well owners are responsible for their own water testing and filtration. If you use a private well, you should use a water filter that can reduce microplastics as a precaution.
Where Do Microplastics in Drinking Water Come From?
Microplastics in drinking water come from many different sources. Most are created when larger plastic items break down into smaller pieces.
The following are the main sources of microplastics in drinking water:
- Plastic bottles, bags, and packaging that slowly break apart.
- Synthetic clothing fibres are released during washing.
- Tyres wear particles from roads.
- Wastewater discharge.
- Rainwater runoff carrying plastic debris.
- Tiny plastic particles falling from the air.
- Plastic pipes, containers, and packaging that come into contact with water.
The World Health Organisation says that dirty water from homes, factories, and rainwater washing plastic off the land are two main ways microplastics get into drinking water.
How Do You Test for Microplastics in Drinking Water?
There is currently no reliable and inexpensive home test for microplastics in drinking water.
Testing for microplastics requires laboratory equipment such as:
- Microscopy
- Fourier-transform infrared spectroscopy (FTIR)
- Raman spectroscopy
If you want a water test for microplastics, your best options are:
- Check whether your water utility publishes microplastic data.
- Send a sample to a specialised laboratory.
- Use a certified filter as a precaution.
Any product that provides a simple at-home microplastic detection test should be treated carefully because accurate testing is difficult.
How Do You Remove Microplastics From Drinking Water?
To remove microplastics from drinking water, there are many technologies that are used to remove microplastics from drinking water, but some work much better than others.
The following table shows a comparison of microplastic filters:
| Method | Effectiveness | Removes Nanoplastics | Notes |
| Reverse Osmosis | Excellent | Yes | Removes more than 99% of particles |
| Ultrafiltration | Very Good | Some | Depends on membrane size |
| Nanofiltration | Excellent | Yes | Effective for very small particles |
| Distillation | Excellent | Yes | Produces purified water |
| Carbon Block (<1 micron) | Good | Some | Choose NSF/ANSI 401 certified filters |
| Basic Pitcher Filters | Limited | No | Usually cannot capture the smallest particles |
Reverse osmosis is currently the most effective home option for removing microplastics and many nanoplastics.
Does Boiling Water Remove Microplastics?
Boiling alone does not reliably remove microplastics. A 2024 study found that boiling hard water for five minutes can cause some microplastics to stick to mineral deposits that form during heating. If those minerals are then filtered out, up to about 90% of microplastics may be removed in hard water. However, this method works much less effectively in soft water and does not remove all nanoplastics.
How Can You Avoid or Reduce Microplastics in Your Drinking Water?
You cannot completely avoid microplastics, but you can reduce your exposure.
The following are some helpful steps:
- Use a reverse osmosis or NSF/ANSI 401 certified filter.
- Drink filtered tap water instead of bottled water when possible.
- Store water in glass or stainless steel containers.
- Avoid heating food or water in plastic containers.
- Do not leave plastic bottles in direct sunlight or high heat.
Reducing the use of single-use plastics helps lower the amount of plastic entering the environment.
Are Microplastics in Drinking Water Bad for Your Health?
Scientists are still studying the health effects of microplastics in drinking water.
The World Health Organisation said in its 2019 report that there was no clear evidence that microplastics in drinking water cause a health risk at current levels. However, the organisation also said that more research is needed. Since then, researchers have found microplastics and nanoplastics in blood, lungs, the placenta, and artery plaque. A 2024 study linked microplastics in artery plaque with a higher risk of cardiovascular problems, but this shows an association and does not prove that microplastics caused those problems. This information is for educational purposes and should not be considered medical advice.
What Did the WHO Say About Microplastics in Drinking Water?
The WHO’s 2019 report and 2022 update concluded that there is no clear proof of harm from current exposure levels, but data remain limited. The organisation also noted that particles larger than 150 micrometres are unlikely to be absorbed by the human body and that better water treatment can remove many microplastics.
What Are the Health Effects of Microplastics on the Body?
Researchers have found microplastics in blood, lungs, liver, placenta, breast milk, brain tissue, and artery plaque.
Early studies suggest possible links to inflammation and cardiovascular problems, but scientists have not yet proven that microplastics directly cause these health conditions.
How Much Microplastic Is in Bottled Water Compared to Tap Water?
Current studies show that bottled water contains far more plastic particles than tap water. One study found that 240,000 particles per litre in bottled water, while tap water often contains only a few to several dozen particles per litre.
What Are the Best Water Filters for Microplastics?
A water filter is the best precaution for water containing microplastics.
The following are the best water filters for microplastics:
- Reverse osmosis systems
- Nanofiltration systems
- Ultrafiltration systems
- NSF/ANSI 401 certified filters
Basic carbon pitcher filters are usually not enough to remove the smallest particles and nanoplastics.
Is There a Legal Limit for Microplastics in Drinking Water?
No. There is currently no enforceable drinking water limit for microplastics anywhere in the world. California is the first place to define microplastics and require testing in large water systems. The US EPA does not currently have a federal standard, and there is no separate North Carolina standard.
What Are Microplastics and How Do They Form?
Microplastics are tiny pieces of solid plastic.
They form in two main ways:
- Secondary microplastics: Larger plastic items break apart because of sunlight, heat, and friction.
- Primary microplastics: Tiny plastic particles are intentionally made small, such as microbeads and synthetic fibres.
These particles can move through the environment and eventually enter rivers, lakes, groundwater, and drinking water supplies.
Frequently Asked Question
Are microplastics really found in tap and bottled water?
Yes. Tap water typically contains a few to several dozen microplastic particles per liter. Bottled water often contains much higher levels, averaging around 240,000 particles per liter.
Are microplastics in drinking water harmful to health?
The long-term health effects are still being studied. While the WHO has found no clear evidence of harm at current levels, microplastics have been detected in human blood, lungs, and artery plaque.
What is the best water filter to remove microplastics?
Reverse osmosis filters remove over 99% of microplastics, including many nanoplastics. NSF/ANSI 401-certified carbon filters also help reduce larger microplastic particles.
Does boiling water remove microplastics?
Not reliably. Boiling may reduce some microplastics in hard water when followed by filtration, but it is much less effective than reverse osmosis.
How can you reduce microplastics in drinking water?
Use a reverse osmosis or NSF/ANSI 401-certified filter, choose filtered tap water over bottled water, and store water in glass or stainless steel containers.