Yes. Multiple independent studies have detected plastic particles in bottled water, including in major brands, and newer techniques that can see much smaller particles find far more of them than older methods did. What is far less settled is what that means for health, and no drinking water standard currently sets a limit on them.
Where the particles come from
Some come from the bottle and its cap: opening and reclosing a bottle abrades plastic, and heat and time make that worse, which is why a case left in a hot car is a poor choice. Some come from the source water itself, since plastic fragments are widespread in surface and ground water. Some come from the bottling line. That mix is why the counts vary so much between brands and between studies, and why one brand testing well is not a general result.
Nothing regulates them yet
This is the honest position. Every community water system publishes an annual Consumer Confidence Report on the supply, and the EPA maintains a finder for those reports, but microplastics are not among the regulated parameters that appear on one. Bottled water is regulated as a food product and is likewise not tested against a microplastics limit. So no label and no report tells you what is in the bottle, and the absence of a number is not evidence of absence.
Tap water is not exempt either
Plastic particles have been found in tap water as well, so switching to bottled water to avoid them is not a clean escape and it is expensive. The meaningful difference is that a household can filter its own tap water and cannot filter the inside of a sealed bottle. That is the practical argument for treating the tap instead: control over the last stage before the glass.
What filtration can realistically do
Microplastics are particles, so mechanical filtration works on them in a way it does not on dissolved contaminants. A fine sediment filter catches larger fragments, a solid carbon block with a fine rating catches more, and reverse osmosis rejects particles well below that. None of this is certified against a microplastics standard because no such standard exists, so judge by the filter's particle rating instead. Our best water filter for microplastics guide compares those ratings.
Questions people ask about are there microplastics in bottled water
Is bottled water worse than tap water for microplastics?
Studies have found particles in both. Bottled water adds the bottle and cap as sources, and unlike tap water you cannot filter it yourself.
Is there a legal limit for microplastics in drinking water?
No. Microplastics are not a regulated parameter, so they do not appear on a utility's annual report or on a bottled water label.
Does a filter remove microplastics?
Filtration works on particles, so a fine carbon block or a reverse osmosis membrane reduces them. Judge by the filter's particle rating, since no standard exists.