The Unpleasant Reality That Could Be Hiding in Your Reusable Water Bottle Lid

Staying hydrated is key, but hitting your daily goal of 64 ounces can be a challenge unless you carry water with you. That’s where reusable water bottles come in—durable, refillable, and more eco-friendly and cost-effective than disposable plastic bottles.

Drinking water is essential, but drinking from a dirty bottle is not. Many reusable water bottles feature rubber seals or plastic threads in their lids for a snug fit, but these same spots can become breeding grounds for mold.

How Risky Is a Moldy Water Bottle Lid?

When a water-filled bottle sits in warm conditions for too long—like in the sun, tossed in your car for days, or stuck in a damp dishwasher—mold spores can find the perfect environment to thrive.

Aside from being downright unpleasant, mold can pose serious health risks when inhaled or ingested. The CDC states that mold exposure can trigger allergic reactions like nasal congestion, sore throat, coughing, wheezing, burning eyes, or skin rashes. These symptoms can be more severe for individuals with asthma. Those with weakened immune systems or chronic lung conditions may also be at risk of developing lung infections from mold.

How to Get Rid of Mold on a Water Bottle Lid

Don’t throw away that moldy lid just yet—there’s an easy fix! This method also works for removing mold from between the lid and rubber seal of glass storage containers.

Fill a sink with 10 parts warm water to 1 part bleach and let the lids soak for about 10 minutes to eliminate the mold. Afterward, run them through the dishwasher to rinse away the bleach.

No dishwasher? No problem. Drain the bleach solution, rinse the sink thoroughly, then fill it with warm soapy water to scrub the lids clean. Whether you clean the lids in the dishwasher or by hand, be sure to dry them thoroughly to prevent mold from coming back.

Give all your water bottle lids a good cleaning about once a month, or whenever you spot mold on one of them.

Can Water Bottles Get Moldy Too?

Yes, both plastic and stainless steel water bottles can develop mold. This mold can be harder to spot since these bottles are often opaque and have narrow openings, making it tricky to check inside.

If your water bottles are showing signs of visible mold, strange odors, or black particles when you pour the water out, it’s time to disinfect them. There are several methods to do this effectively:

• Boiling: Boil stainless steel water bottles. Bring a large pot of water to a boil and submerge the stainless steel water bottles in the boiling water for at least 15 minutes. Allow the water to cool before removing the bottle to prevent burns. Place the bottles upside-down in a rack that allows airflow all around the bottles so they dry thoroughly.
• Vinegar: For plastic or stainless steel bottles, fill the bottles with half distilled white vinegar and half water. Shake the mixture in the bottles and then allow them to sit overnight. Pour out the vinegar/water, and wash the bottles in the dishwasher or by hand in the sink. Allow the bottles to fully dry before using.
• Bleach: Submerge your water bottles in the same sink with the water/bleach solution that you’re cleaning the lids in. After they’ve soaked for 10 minutes, use a bottle brush to scrub them inside and remove any mold that may have gotten dislodged. Then wash the bleached bottles in the dishwasher or by hand and allow them to dry thoroughly.

Once your water bottles are mold-free, make sure to wash and dry them thoroughly after each use to keep them clean. If mold reappears, you now know exactly how to tackle it.