Here’s How Long You Should Be Reusing That Plastic Water Bottle

It’s common knowledge that drinking out of plastic water bottles isn’t the best idea. Still, even though there are plenty of environmentally-friendly options out there, we sometimes find ourselves grabbing a disposable plastic water bottle during a moment of thirst. It happens! And if you do that, you might think that you can reverse some of the damage by reusing the bottle a bunch of times, to save both the Earth and your wallet. But should you really keep one for more than a few days? If you’re going to do this, you need to know how long you really could be reusing that plastic water bottle.

There are a few myths out there that claim that when you reuse a plastic water bottle, the plastic starts to break down, leaching harmful chemicals into your water that you are then ingesting. No one really wants to do that, so naturally, that sounds pretty terrifying. But is it true?

The answer isn’t quite as simple as it should be.

According to the Huffington Post, in one article printed in the journal Practical Gastroenterology, experts said that commercial bottled water manufacturers don’t recommend consumers reuse their disposable bottles. This is because “everyday wear and tear from repeated washings and reuse can lead to physical breakdown of the plastic, such as visible thinning or cracks. Bacteria can harbor in the cracks, posing a health risk.”

The Federal Drug Administration (FDA) tells a slightly different story. According to Spoon University, most of the plastic water bottles in the U.S. are made from polyethylene terephthalate (PET), which the FDA has determined is safe for both single and repeated use. So, it looks like bottled water manufacturers don’t think they should be reused much, while the FDA thinks it’s no problem.

But there is one thing everyone can agree on: reusing your plastic water bottle without washing it is going to allow lots of bacteria to grow in there.

In that same Practical Gastroenterology article, experts said that “reuse of plastic water bottles can lead to bacterial contamination unless washed regularly.” Other studies back this up. One study from 2002 looked at 76 samples of water from water bottles, some of which had been reused for months on end without being washed. Nearly tw0-thirds of the samples had bacterial levels that exceeded drinking water guidelines.

Even though there’s nothing in water, and you might think it’s safe to allow it to sit around, unwashed bottles are a perfect breeding ground for bacteria because they have backwash, moisture, and they’re the right temperature. Ick.

If you’re going to reuse a plastic water bottle, the FDA and other experts agree that you need to wash it regularly. The FDA says you should wash the bottle out with hot soapy water between each use.

If you do that, you can reuse your plastic water bottle as long as it doesn’t appear to be breaking down or showing any cracks, which really depends on how often you use it. Once you notice it looks worn and old, you’re better off getting something new. And of course, your best bet is to use a different kind of reusable bottle, like one made of metal or glass.