A: "It's not a good idea," said William Sonzogni, a UW- Madison environmental chemist.

The inside surface of those bottles can be a good place for bacteria to grow, and the small opening makes a thorough cleaning difficult, even in the dishwasher.

Sonzogni directs the Environmental Health Laboratory of the state Laboratory of Hygiene. He said research shows that the risk from the plastic breaking down is negligible.

There are rigorous standards for plastics that come in contact with food or drink. Most beverage bottles sold in the U.S. are made from polyethylene terephthalate (PET), which the FDA has approved.

However, commercial water bottles are designed for one use and then recycling. They don't hold up well to repeated use, and rinsing with hot water could warp them.

"You're better off using a sports bottle with a wide opening," Sonzogni said. "They're made from more durable plastic that is designed to be reused."

Bacteria thrive in moist environments, so stick to good hygiene practices. After every use, wash your sports bottle with hot soapy water and rinse well. Scrub the inside, neck and lid with a brush, and allow the bottle to air dry completely between uses.

- Produced in cooperation with University Communications

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