Boiling Water May Remove Microplastics and Nanoplastics From Tap Water

Tiny plastic fragments are entering our bodies in worrying amounts, especially through the food and drinks we consume.

Boiling water to remove nano/microplastics

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

The researchers introduced nanoplastics and microplastics into the water, boiled it, and then filtered out any precipitate 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.

See the video below for an overview of the findings:

In certain tests, boiling and filtering removed as much as 90 percent of NMPs, although the result depended on the type of water used.

Crucially, most households already have everything required to use this approach 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.

Hard tap water yielded a higher removal rate for NMPs. When heated, this type of water naturally produces limescale, or calcium carbonate.

The chalky material often found inside kitchen kettles coats the surface of plastic particles. As temperature changes force calcium carbonate out of the water, it forms a crust that effectively traps the plastic fragments.

"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 in soft water, which contains less dissolved calcium carbonate, around one quarter of the NMPs was captured.

The researchers say that pieces of plastic coated in limescale can then be taken out with a basic filter, such as the stainless-steel mesh used for straining tea.

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

To put the method through a more demanding trial, the team added greater numbers of nanoplastic particles and still reduced their quantity effectively.

"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 researchers hope boiling water could become more common as plastic continues to spread across the world.

Microplastics in drinking water

Minute pieces of plastic are becoming an ever-larger issue. Microplastics come from clothing, kitchen utensils, personal-care products and innumerable other everyday items.

Their resilience means they remain in the environment, including within human bodies.

Many people around the world are already contaminated with microplastics, and daily exposure continues because these troubling particles are subject to little regulation.

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

Since plastic production began, approximately 9 billion metric tonnes of plastic have been made worldwide. Much of it has gradually worn down into smaller and smaller fragments rather than genuinely decomposing, creating a fine plastic dust that now reaches throughout the planet.

The latest review suggests that wastewater treatment plants do remove many of these tiny particles, but the amount removed remains insufficient.

Potential health effects of microplastics

Although the precise harm plastic may cause inside our bodies remains uncertain, it is plainly not a healthy thing to ingest.

Plastic has already been associated with alterations to the gut microbiome and to the body's antibiotic resistance.

The researchers behind the study want further work to examine whether boiled water can prevent artificial materials from entering our bodies and potentially offset some of the concerning microplastic effects now being identified.

"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 study was published in Environmental Science & Technology Letters.

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