Sanitary Water Bottles

Reusing unwashed water bottles, even if you’re “only” drinking water out of it, puts your mouth in intimate contact with a wonderful bacterial breeding ground.

Bacteria grow really well in moist, warm environments. Narrow-mouthed plastic water bottles are difficult to scrub and especially friendly to bacterial growth. In a 2003 study, Canadian researchers collected samples from water bottles that were being reused and found that almost two-thirds contained bacterial contamination that exceeded safe drinking water guidelines.

So, you have to vanquish the bacteria between uses, but here’s the snag to washing your bottle: cleaning the things might actually make them unsafe in a different way. Bisphenol A or BPA is a chemical compound used in the making of polycarbonate plastics, including some kinds of plastic bottles. It mimics estrogen and binds to the same receptors in the human body as natural hormones. Over the years, it’s been linked to everything from cancer cell growth to developmental and neurological issues.

When you give a bottle a good scrub, you’re wearing down the plastic and allowing BPA and other chemicals to leach from it and into the bottle’s contents. Using the bottles for hot liquids, putting them in the dishwasher, and trying to sterilize them with boiling water all do the same thing. Dr. Scott Belcher, a pharmacolgist at the University of Cincinnati, has done several studies on BPA in bottles and found that heat is a big factor in its release. One study showed that when BPA-containing drinking bottles are exposed to boiling water, the chemical is released 15 to 55 times faster than normal. “These are fantastic products and they work well,” Belcher told Scientific American. “[But] based on my knowledge of the scientific data, there is reason for caution. I have made a decision for myself not to use them.”

Stainless Steel Water Bottles

As for the alternative to polycarbonate plastics, PET, the jury is largely still out on how safe it is. The contents of the bottle and the temperature at which it’s stored and washed both seem to influence the amount of plastic components leaching from it and the rate at which they leach. 

So what’s a person to do to avoid illness from both creepy crawlies and plastic components? Regularly-washed glass or stainless steel water bottles seem to be the way to go. They’re dishwasher-safe and easier to clean, and provide less favorable breeding grounds for germs. They’re also chemically safe, according to all current studies.