Is it safe to store drinking water in polypropylene containers for the fridge?
No. Even cold water pulls nanoplastics out of polypropylene.
What's actually in it
Polypropylene (the #5 plastic) shows up as Tupperware, Brita pitchers, fridge water bottles, and takeout containers. It's advertised as the "safer" food-grade plastic because it doesn't contain BPA and tolerates higher temperatures. That doesn't mean it's inert. Every polypropylene container sheds microscopic and nano-sized particles into whatever it holds.
Hot liquids pull out more particles, which is well known. What's newer is the data on cold water, which most people assume is fine.
What the research says
A 2025 study in J Agric Food Chem tested nanoplastic release from polypropylene food containers into hot and cold water. Hot water released more, as expected. Cold water also released measurable nanoplastics over storage periods. The take-home was that refrigerated water in a polypropylene pitcher carries a steady microplastic load, not zero.
A glass pitcher with a silicone seal solves the issue. Those cost about the same as a plastic pitcher once you factor in filter replacement. For a water bottle, stainless steel or glass both work. If polypropylene is unavoidable (a good water filter like Berkey uses plastic housing), don't store water in it for more than a day or two. Rinse and refill daily rather than filling once a week.
The research at a glance
| Study | Journal | Year |
|---|---|---|
| Release of Nanoplastics from Polypropylene Food Containers into Hot and Cold Water. | J Agric Food Chem | 2025 |
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