Can microplastics in drinking water bottles contaminate every glass you pour?

What's actually in it

Plastic water bottles are made from PET (polyethylene terephthalate), and reusable bottles use polycarbonate, polypropylene, or Tritan plastics. All of these shed micro- and nanoplastic particles into the liquid they hold. Squeezing, temperature changes, sunlight exposure, and repeated use all accelerate the shedding.

Milk cartons and juice boxes also use plastic linings that contribute particles. Basically, if your drink comes in or touches plastic, it picks up plastic particles.

What the research says

A 2025 study in Environ Monit Assess examined microplastics in commercially sold drinking water bottles and milk packaging. The researchers found microplastic particles in every sample tested. The dominant plastic types matched the container materials: PET from water bottles and polyethylene from milk packaging.

Particle counts varied by brand and container type, but none were microplastic-free. Some bottles had hundreds of particles per liter. The particles ranged from fragments visible under a microscope to tiny fibers.

People who drink the recommended 8 glasses of water a day from plastic bottles could be swallowing tens of thousands of microplastic particles per year from the bottles alone. Glass bottles, stainless steel bottles, or filtered tap water from a glass pitcher all reduce this exposure.