Many people reuse their plastic water bottle without considering the possible health effects. Even with what appears to be proper cleaning, reusing a water bottle has its disadvantages.
Reusing a water bottle without cleaning it can create bacteria that can cause disease. This is especially true in warm weather when bacteria can grow much faster on the moist openings of plastic water bottles.
Simply washing and drying the opening of a water bottle does not completely clean it of bacteria. The inside of the water bottle must be cleaned thoroughly with a brush, warm water and cleanser. Then it must be allowed to air dry.
People should avoid sharing plastic water bottles. Germs and bacteria can transfer from person to person on the opening of the bottle, and on the water that has condensed on the outside of the bottle as well.
The New Zealand Food and Safety Authority reminds us that a clean water bottle is only safe when filled with clean water for drinking. Use filtered water if the decision is made to refill plastic water bottles.
According to the American Cancer Society, there is no danger in contracting cancer from a reused water bottle. A myth had circulated that reusing a water bottle breaks down the bottle's plastic and dangerous chemicals can get into the water. This is not true.