Bottled water can contain thousands of tiny plastic particles, or "microplastics," according to a recent study.
Microplastics are tiny fragments and fibers broken down from a larger piece of plastic, and they're found pretty much everywhere.
They are also found in tap water, but at much lower levels than bottled water. The high number of particles in bottled water could come from manufacturing, or just from opening the lid.
The effects of ingesting micoplastics are unknown — but it doesn't seem to cause any immediate health problems.
While tap water may have less plastic than bottled, it's only "safer" if it's clean — as in not contaminated with germs — which may not be the case in some places.
However, researchers still suggest limiting your consumption, and exposure to, plastic in your daily life.
More research is underway.