There's a Surprisingly Easy Way to Remove Microplastics in Drinking Water

Tiny fragments of plastic are ending up deep inside our bodies in worrying amounts, especially through what we eat and drink.

Boiling tap water to remove nanoplastics and microplastics (NMPs)

In 2024, researchers in China identified a straightforward, effective way to strip these particles from water. They tested both soft water and hard tap water (which contains more dissolved minerals).

The scientists first spiked the samples with nanoplastics and microplastics, then boiled the water and filtered out the precipitates that formed.

"Tap water nano/microplastics (NMPs) escaping from centralized water treatment systems are of increasing global concern, because they pose potential health risks to humans via water consumption," the researchers write in their published paper.

Watch the video below for a summary of the findings:

Depending on the water type, the boiling-and-filtering approach removed as much as 90 percent of the NMPs.

A major advantage is its accessibility: most households can do this using equipment they already have in the kitchen.

"This simple boiling water strategy can 'decontaminate' NMPs from household tap water and has the potential for harmlessly alleviating human intake of NMPs through water consumption," write biomedical engineer Zimin Yu from Guangzhou Medical University and colleagues.

Why hard water works better: limescale and calcium carbonate

Hard tap water shed a higher proportion of NMPs, largely because it naturally produces limescale (calcium carbonate) as it heats.

That chalky build-up-commonly found inside kitchen kettles-forms on plastic surfaces when temperature-driven changes force calcium carbonate out of solution, effectively trapping the fragments within a crust.

"Our results showed that nanoplastic precipitation efficiency increased with increasing water hardness upon boiling," the team writes.

"For example, from 34 percent at 80 mg L^−1 to 84 percent and 90 percent at 180 and 300 mg L^−1 of calcium carbonate, respectively."

Even with soft water, where less calcium carbonate is dissolved, around a quarter of the NMPs were still captured.

The researchers add that lime-encrusted plastic bits can then be removed with a simple filter-such as a stainless-steel mesh strainer used for tea.

What has been found in drinking water-and how boiling performed

Earlier research has detected fragments of polystyrene, polyethylene, polypropylene, and polyethylene terephthalate in drinkable tap water, which people consume daily in varying amounts.

To push their approach further, the team introduced an even higher load of nanoplastic particles, and the number of particles was still effectively reduced.

"Drinking boiled water apparently is a viable long-term strategy for reducing global exposure to NMPs," write Yu and team.

"Drinking boiled water, however, is often regarded as a local tradition and prevails only in a few regions."

The scientists would like to see the practice adopted more widely as plastics continue to spread across the planet.

Why microplastics are an expanding concern

Small pieces of plastic are becoming an ever bigger problem. Microplastics come from clothing, kitchen utensils, personal care products, and many other everyday items.

Because these materials are so durable, they persist in the environment-including within human bodies.

Not only are many people already contaminated by microplastics, but exposure continues daily, as regulation of these pervasive specks remains limited.

A 2025 literature review from The University of Texas at Arlington suggests that a substantial share of microplastic exposure may come from drinking water, since wastewater treatment plants still do not remove microplastics effectively.

Since plastic production began, roughly 9 billion metric tons of plastic have been produced worldwide. Much of it has gradually degraded into ever-smaller pieces without fully breaking down, creating a fine plastic dust that now permeates the Earth.

The same review indicates that wastewater treatment plants do remove many of these particles-but not enough.

Possible impacts on health and next steps

Although it is still unclear exactly how harmful this plastic is inside our bodies, it is evidently not a healthy thing to ingest.

Plastics have already been associated with shifts in the gut microbiome and with changes in the body’s antibiotic resistance.

The researchers behind the boiling study want further investigation into how boiled water might help keep synthetic materials out of our bodies-and potentially help counter some of the troubling effects of microplastics that are emerging.

"Our results have ratified a highly feasible strategy to reduce human NMP exposure and established the foundation for further investigations with a much larger number of samples," Yu and colleagues conclude.

The research was published in Environmental Science & Technology Letters.

An earlier version of this article was published in March 2024.