Boiling Tap Water Could Remove Microplastics and Nanoplastics, Study Finds

Tiny shards of plastic are turning up far inside the human body in worrying amounts, with food and drink a major route of exposure.

Research suggests there may be a practical step you can take to reduce what you swallow.

In 2024, researchers in China reported a straightforward, effective way to strip these particles from water.

Why nano/microplastics in tap water are a concern

The scientists tested both soft water and hard tap water (which contains more dissolved minerals). Into each sample they introduced nanoplastics and microplastics, then brought the water to the boil and filtered out the resulting precipitates.

Their experiments indicated that boiling followed by filtering can markedly cut the plastic contaminants you might otherwise ingest.

"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 explained in their published paper.

Watch the video below for a summary of the findings:

In some tests, the boil-and-filter method removed as much as 90 percent of NMPs, although performance differed depending on the water.

A major advantage is its accessibility: most people can do this using items already 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," biomedical engineer Zimin Yu from Guangzhou Medical University and colleagues explained.

How boiling and filtering traps NMPs (hard vs soft water)

Hard tap water saw a larger share of NMPs removed, because heating naturally encourages the formation of limescale (calcium carbonate).

The same chalky deposit commonly found inside kettles can develop on the surface of plastic particles. As temperature shifts push calcium carbonate out of solution, it coats the fragments, effectively locking them into a crust.

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

"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 NMPs were still captured.

The researchers say any lime-coated plastic particles can then be taken out using a simple filter, such as a stainless-steel mesh strainer used for tea.

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

To stress-test the approach, the team added an even higher load of nanoplastic particles, and still found their numbers were effectively reduced.

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

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

The researchers hope the habit may spread as plastic pollution continues to expand worldwide.

The broader microplastics problem and what we know so far

Small plastic particles represent a growing issue. Microplastics can shed from clothing, kitchen tools, personal care products, and countless other everyday items.

Because they are so durable, they persist in the environment-and that includes inside human bodies.

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

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

Since plastic production began, roughly 9 billion metric tonnes of plastic have been made globally. Much of it has gradually degraded into smaller and smaller pieces without truly breaking down, creating a fine plastic dust that now permeates the planet.

The new review indicates wastewater treatment plants do capture many of these tiny particles-but not enough.

Although the precise harm these plastics may cause in our bodies is still not fully clear, they are plainly not a healthy addition to the diet.

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

The team behind the boiling study wants further work on how boiling water might help keep synthetic materials out of the body-and potentially blunt some of the worrying effects of microplastics now being reported.

"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.