Tiny pieces of plastic are slipping into our bodies every day through the food and water we consume. Now, new research suggests that a simple kitchen habit could drastically lower that risk.
In 2024 scientists in China discovered that boiling tap water before drinking it can significantly reduce the amount of microplastics and nanoplastics it contains. The method was tested on both soft and hard tap water, with researchers first adding microplastics to the samples, then boiling and filtering them.
The results were promising: in some cases, up to 90 percent of the plastic fragments were removed. The effectiveness depended on water type, with hard water showing the greatest results.
“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,” explained researchers from Guangzhou Medical University and Jinan University in their published findings.
Limescale Trap: How Boiling Captures Plastic
The process works because when hard water is heated, it naturally forms limescale (calcium carbonate). This chalky buildup, often seen inside kettles, traps plastic particles as it precipitates out of the water. Once caught in this crust, the fragments can be easily removed using a simple filter, like a stainless-steel tea strainer.
The study found that the harder the water, the better the results. For example, precipitation efficiency jumped from 34 percent in water with 80 mg/L calcium carbonate to 84 percent and 90 percent in water with 180 mg/L and 300 mg/L, respectively. Even soft water, with lower mineral content, showed a reduction of about 25 percent.
A Simple Habit With Global Impact
Past studies have already confirmed that our drinking water often carries particles of common plastics such as polystyrene, polyethylene, polypropylene and PET. By boiling water, the Chinese researchers demonstrated that even higher levels of added plastic could be reduced effectively.
“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,” said biomedical engineer Zimin Yu and colleagues.
While boiling water is already a cultural tradition in some regions, the researchers hope it becomes a wider global practice, especially as plastics continue to infiltrate daily life. Though the long-term health effects of ingesting microplastics are still being studied, early evidence links them to gut microbiome changes and increased antibiotic resistance.
The study published in Environmental Science & Technology Letters concludes that boiling water offers a practical, affordable way to reduce plastic exposure and sets the stage for further research on protecting human health from this hidden pollutant.