We know the benefits of using a reusable water bottle include helping both your body stay hydrated and keeping the Earth clean. But, have you thought about how often you should be cleaning that bottle? 

Tests done on water bottles have revealed they can sometimes contain up to 40,000 times the bacteria of a toilet seat due to inappropriate washing! “Ideally you should be washing your bottle and all the parts daily with warm soap and water,” Dr. Roopa Shah, SSM Health Family Medicine provider, suggests as a way to prevent harmful bacteria and mold from growing inside, which could make you sick.

Her tips for a good scrub include:

• Use a bottle brush for the body of your bottle

• A smaller bristled brush will clear the spout and straw of any mold or bacteria

• Do a sanitizing clean once per week by soaking the bottle in equal parts hot water and vinegar

Another way to sanitize is to soak the bottle and parts in a solution of one teaspoon of bleach and eight ounces of water, and then wash again thoroughly with soap and water.

If you do notice mold has formed inside your water bottle, immediately stop using it, advises Dr. Shah. Check and see if it’s dishwasher safe, and if so, put it on the hottest setting in the dishwasher to get rid of mold.

“Hot water and detergent are great at getting rid of mold,” Dr. Shah said. “Mold likes moist environments, which is what makes water bottles particularly susceptible to growth. If you notice the mold is too difficult to clean from all the parts of your water bottle, it’s best to purchase a new one.”

If you have been drinking from a moldy water bottle, Dr. Shah says not to panic, and while it can feel gross to know you have been drinking from a moldy bottle, most people with healthy immune systems will not suffer any illness or consequences from doing so. But if you notice any nausea, vomiting, abdominal pain, headaches or fever after you’ve been using it, you should contact your medical provider.