A reusable water bottle is a must for anyone who wants to stay hydrated and reduce plastic waste by ditching ... a lot of bacteria and potentially grow mold. “Mold thrives in moist environments ...

Though the average lifespan varies, experts suggest that certain types—like hard plastic bottles ... It’s not uncommon for mold to develop on the inside of a water bottle over time.

Whether it’s stainless steel, glass or plastic, Dr. Sumego said all reusable water bottles need to be regularly washed to ...