A world health group is now studying what that could mean.
The research started after a group at the State University of New York at Fredonia found microplastics in tap water.
Bottled water is bottled tap water, so the researchers wanted to find out if there is just as much plastic in bottled water.
They discovered there is more.
"So, think of a period at the end of the sentence or a grain of salt or a grain of sand."
The team found twice as much plastic in bottled water as it had in tap water.
A bottle of Evian water had up to 256 pieces of plastic.
Aquafina had nearly 1,300 pieces of plastic and one bottle of Nestle Pure Life had more than 10,000 pieces.
"On average, within every liter of bottled water, we tested we found 325 pieces of microplastic," Mason said.
The plastic found in the bottled water is the same kind used to make the bottle and cap.