Short Answer
When Columbia University researchers looked at bottled water with a new laser imaging method, they found about 240,000 tiny plastic particles in an average liter. Most of those were nanoplastics, pieces small enough, the NIH notes, to enter the body's cells and tissues. If you'd rather drink less of that, one easy step is to stop buying single-use bottles and refill your own glass or stainless steel jug instead.
What the study found
The study came out in the Proceedings of the National Academy of Sciences in January 2024, and the NIH summary breaks it down well. The team tested three popular bottled water brands. Here's what they saw:
- About 240,000 plastic pieces per liter, on average.
- About 90% were nanoplastics, which are smaller than 1 micrometer. Microplastics are bigger: anywhere from 5 millimeters (smaller than a sesame seed) down to 1 micrometer.
- That's 10 to 100 times more than earlier studies counted, mostly because those studies focused on larger microplastics.
- The most common plastics were polyamide (a type of nylon) and PET, the plastic used to make water bottles.
The researchers didn't name the brands, so any list of the "worst" brands you see online didn't come from this study.
Is it bad for you?
Plastic particles have already been found in human blood, lungs and placentas, according to the NIH. The NIH also says the possible health effects are still unproven and unknown. Nanoplastics are so small that they've been hard to detect and study at all.
Our take: you don't need to panic, and you don't need to wait for a final verdict to cut back. If something you drink every day comes with plastic you can't see, using fewer plastic bottles is a sensible move.
Where does the plastic come from?
PET showing up makes sense. It's what the bottles are made of. Polyamide is interesting, because the NIH notes it's often used to help filter and purify water.
That second point matters for refill stations too, so we'll be straight with you: refill machines filter water too, and no one has shown that refill water is plastic-free. What you can control is the container. Our inference: if your water sits in your own glass or stainless steel jug instead of a thin single-use bottle, you're cutting out the bottle, one likely source of the PET.
What you can do
Our pick: refill a glass or stainless steel jug. It's the simplest swap that takes single-use bottles out of your routine, and it usually costs less than buying cases.
- Switch to a reusable jug. Glass or stainless steel if you want to keep plastic out of the container. Keep it clean with our jug cleaning and storage guide.
- Refill instead of buying cases. You'll likely save money too. See refilling vs. bottled water cost.
- Pick your water type. Most refill machines in our directory offer reverse osmosis water. Some also have alkaline, and natural springs are another option.
- Find a station near you. Search your city on PureWaterFinder, or start with Denver, Los Angeles or Tampa.
- Give the machine a quick check before you fill: here's our 30-second checklist.
FAQ
Should I stop drinking bottled water because of microplastics?
That's your call. If you want less plastic in your routine, refilling a glass or stainless jug is the simplest swap, and it usually costs less too.
Which bottled water brands have the most microplastics?
The Columbia study tested three popular brands but didn't name them, so we can't tell you.
Are microplastics and nanoplastics the same?
No. Microplastics run from 5 mm down to 1 micrometer. Nanoplastics are smaller than 1 micrometer, and they made up most of what the study found.
Does refill water have microplastics?
No one has published a count for refill stations that we know of. Filling a glass or stainless jug instead of buying single-use bottles cuts out the bottle itself.