Does bottled water have fewer microplastics than tap water?
No. A 2026 study found bottled water had higher microplastic and nanoplastic particle concentrations than treated tap water in the samples tested.
What's actually in it
Tap water can contain microplastics from source water, treatment systems, pipes, and household plumbing. Bottled water can also pick up particles from processing, caps, and plastic bottles.
PET is the plastic used in many single-use water bottles. Heat, shaking, and long storage can make PET bottles release more nano- and microplastics.
What the research says
A 2026 study in Science of the Total Environment compared samples from 4 drinking-water treatment plants and 6 bottled-water brands. The study found bottled water had significantly higher microplastic and nanoplastic particle concentrations than treated drinking water, especially for smaller particles.
Bottled water was high in polyamide, PET, and polyethylene particles. Treated drinking water was most abundant in polyamide and polyester particles, including PET.
A 2026 study in Water Research tested 8 U.S. bottled-water brands. Heat and shaking increased nanoparticle release from PET bottles, with the highest release under combined heat and shaking.
Tap water quality depends on where you live. Still, bottled water is not a reliable way to avoid plastic particles. Filtered tap water stored in glass or stainless steel is a better daily habit.