How to remove mould from a water bottle

Updated March 28, 2018

Mould thrives in dark, moist environments. Reusable water bottles are often the perfect breeding ground for mould because the inside of the bottle is always wet. Even after washing, you may not thoroughly dry your bottle before using it or putting it away. If you notice a black or green residue in your bottle, especially along the seal where the lid goes on, you need to remove the mould immediately. Not only can it make your water taste and smell strange, but it can also make you unwell.

Run the toothbrush through the hot cycle on your dishwasher to sanitise.

Put your gloves on and mix a solution of 4.5 litres (1 gallon) of water, 5 ml (1 tsp) bleach and 5 ml (1 tsp) baking soda.

Fill your water bottle with the bleach solution and allow it to sit overnight.

Apply baking soda to the toothbrush and scrub the lid or cap to your water bottle thoroughly. Pay particular attention to the rubber seals on the bottle and the lid or cap. If the seals are removable, take them off and scrub underneath.

Rinse your water bottle and lid well. Wash the water bottle by hand in hot water and air dry, or run it through the dishwasher. Do not put the bottle away until it is completely dry.


Store your bottle separately from the lid or cap to prevent the growth of mould in case there is any moisture left in the bottle.

Store your bottle in the freezer between uses to prevent mould growth.

Wash your bottle often with washing-up liquid and hot water to prevent the growth of mould and bacteria.


Use caution when handling bleach.

Things You'll Need

  • Gloves
  • 5 ml (1 tsp) bleach
  • 4.5 litres (1 gallon) water
  • Baking soda
  • Toothbrush
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About the Author

Jess Jones has been a freelance writer since 2005. She has been a featured contributing writer for "Curve Magazine" and she teaches English composition at a small college in Ann Arbor, Michigan. She received her Master of Arts in English language and literature in 2002.