Worried about the harmful microplastics in your water? You just need to boil and strain it before consumption

Nanoplastics and microplastics (NMPs) are sneaky invaders, hiding in the tap water we drink every day. These tiny fragments of plastic have already been linked to unsettling changes in gut health and antibiotic resistance, raising alarm bells about their impact on our bodies. But here’s some refreshing news: scientists have discovered a surprisingly simple solution — boiling your water.

A kitchen hack for cleaner water

Researchers, led by biomedical engineer Zimin Yu, have found that boiling water and then filtering it can remove up to 90% of nanoplastics and microplastics from tap water. “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,” the team explains.

Even better? You probably already have the tools you need in your kitchen: a pot to boil water and a simple stainless steel mesh to filter out any leftover bits.

How does it work?

The trick lies in the build-up of limescale — or calcium carbonate — when water is heated. If you’ve ever peeked inside a kettle, you’ve seen this chalky layer. When water is boiled, calcium carbonate naturally precipitates out of the solution, forming a crust. This crust traps NMPs on its surface, making it easier to filter them out.

“Our results showed that nanoplastic precipitation efficiency increased with increasing water hardness upon boiling,” the researchers write. For example, in soft water (low in calcium carbonate), the process managed to remove about 25% of NMPs. Meanwhile, in hard water (higher calcium carbonate levels), the process removed up to 90% of NMPs.

The harder the water, the better the results

Hard water, often considered a nuisance because of limescale, might actually be a secret weapon against microplastics. The researchers found that the harder the water, the more effective the boiling process was at capturing and removing plastic fragments.

In water containing 300 mg/L of calcium carbonate, NMP removal reached an impressive 90%. Even at lower levels, such as 80 mg/L, over a third of the plastics were filtered out.

Using a simple tea strainer or other household filters, these lime-encrusted plastic fragments can be easily removed before the water is consumed.

Why it matters

Microplastics aren’t just a problem for the planet — they’re becoming an intimate part of our daily lives. Previous studies have identified plastics like polystyrene, polyethylene, and polypropylene in drinking water. While the long-term effects on human health remain uncertain, the evidence suggests we’re better off without them.

“Drinking boiled water apparently is a viable long-term strategy for reducing global exposure to NMPs,” the researchers say.

For many, boiling water before drinking it is already a cultural norm. But the researchers hope their findings will encourage more people worldwide to adopt this practice as plastics continue infiltrating our water sources.

The findings of this research have been published in Environmental Science & Technology Letters and can be accessed here.