Why Does My Water Bottle Smell? (5 Common Causes)

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Noticed an unpleasant odor from your water bottle? There are a few reasons why water bottles may smell, and we’ve covered them all in this guide.

πŸ“Œ Key Takeaways:

  • A reusable bottle may smell due to odors from the bottle material, a lack of cleaning, improper cleaning, stagnation, or absorption of smells from certain beverages.
  • You can fix a smelly bottle by thoroughly cleaning the bottle, soaking the bottle overnight, and storing the bottle properly.
  • If you can’t get rid of the smell, you might need to replace the bottle with a new one.

πŸ“‹ 5 Causes Of A Smelly Water Bottle

Here are the 5 most common causes of a smelly bottle.

1) Bottle Material

The bottle material is the number-one cause of unusual smells in your water.

Reusable plastic water bottles often carry a mild plastic smell. You’re especially likely to notice this smell when you first open a new bottle. Most manufacturers recommend washing the bottle before using it for the first time, which should remove any residues left over from the manufacturing process and reduce chemical odors and tastes.

Stainless steel bottles may also give off a metallic flavor and smell. This is most likely if your bottle has started to rust or corrode, causing metals to leach into the water. It’s a myth that stainless steel never corrodes.

Plastic and stainless steel water bottles

2) Lack Of Cleaning

A lack of cleaning is another very common reason why your water bottle might start to smell. This problem applies regardless of the material your water bottle is made from.

Cleaning a water bottle removes stagnant water and scrubs the inside surfaces free of mildew, mold, and any other microorganisms that might accumulate in the damp environment.

So, if you don’t clean your water bottle regularly, microbes will have more time to grow inside the bottle. As a result, you’ll notice a dirty or musty smell when you open your bottle lid.

3) Improper Cleaning

If your water bottle smells even though you clean it regularly, improper cleaning might be to blame.

Simply rinsing the bottle with warm water isn’t enough to get it clean. You need to spend time scrubbing the bottle in hot, soapy water with a bottle brush, which will remove any bacteria or nasties from the inside surfaces.

Once you’ve cleaned the bottle, flip it upside down and leave it to air dry, preventing stagnant water from sitting in the bottom of the bottle (which will give it a damp, musty smell even after washing).

4) Stagnation

Let’s say you clean your reusable water bottles regularly and thoroughly. Why do you still notice a wet dog smell?

Stagnation is probably to blame. If you leave even a small amount of water in your bottle overnight before washing it out the next day, odor-causing bacteria may begin to grow. As a result, you’ll notice a nasty smell when you open your bottle lid.

Plus, if you’ve used your bottle for anything other than water, you might notice residual smells of these beverages when you come to fill the bottle again.

Stagnant water in water bottle

5) The Liquid Inside

Sometimes, it’s not the bottle itself that’s to blame for a bad smell, but the liquid that’s inside the bottle.

If your water bottle smells bad, consider what you usually store in the bottle. If you regularly use the bottle to hold juice, soda, or hot drinks, the flavors and smells of these beverages may seep into the bottle material (this is especially common with plastic bottles).

Even if you only use your reusable bottle to hold water, certain contaminants in your water could be to blame for the smell.

Hydrogen sulfide gas, present in some groundwater supplies, makes water smell like rotten eggs, while chlorine, used to disinfect most municipal water supplies, gives water a swimming pool smell.

If you notice any of these smells when you open your reusable water bottle, your water quality is likely to blame – not the bottle itself.

πŸͺ› How To Fix A Smelly Water Bottle

Nobody wants to have to hold their nose when they drink from their water bottle. Here are the best ways to resolve a smelly water bottle, depending on the cause.

Thoroughly Clean The Bottle

Start by cleaning the bottle thoroughly. This should remove any smells associated with a new, unused plastic water bottle, or smells that have accumulated over time due to a lack of washing.

To clean the bottle, fill a bowl with hot water and dish soap, and submerge the bottle in the water. Use a bottle brush to scrub the difficult-to-reach areas. Let the bottle air dry upside-down before reusing.

Make sure to wash the bottle regularly – ideally once a day, or once after every use – to prevent smelly bacteria growth.

Soak The Bottle Overnight

If thorough cleaning doesn’t do the trick, an overnight soak in baking soda water is the next thing to try.

Baking soda has a natural ability to neutralize acidic and alkaline substances, eliminating the foul smell associated with them. It’s natural and non-toxic, making it safe to use for deodorizing stainless steel and plastic water bottles.

Scoop two large tablespoons of baking soda into the water bottle, then fill the bottle with warm water. Leave the bottle to sit overnight, allowing the baking soda to work its magic.

If you have a stainless steel water bottle, try using boiling water or white vinegar to neutralize the stainless steel odor. Fill your bottle with boiling water or white vinegar, then let it sit for a few hours before rinsing with water. Washing the bottle in warm, soapy water will remove any lingering vinegar smell.

Baking soda

Store The Bottle Properly

A simple way to avoid a bad smell in your reusable water bottle is to make sure you’re storing it correctly.

Have enough patience to wait for your bottle to completely dry before putting it in storage. Even a small amount of stagnant water puddled at the bottom of the bottle will begin to smell.

After letting the bottle air dry, store it upright in your cupboard with the bottle cap open, allowing for ventilation. This should reduce the chances of odors returning.

Switch Bottles

Sometimes, cleaning your bottle won’t be enough to eliminate the foul odor.

Old water bottles become cracked, allowing bacteria to build up in difficult-to-access areas, or (in the case of stainless steel water bottles) may begin to rust.

The bottle material itself might be responsible for the smell. Plastic bottles, especially cheap ones, may emit a plastic chemical smell regardless of how much cleaning you do. If your plastic water bottle smells, try switching to a stainless steel bottle, which is less likely to emit an odor.

Switching water bottles

πŸ“‘ Final Word

Great-tasting reusable bottled water is achievable – you just need to make sure to take the appropriate action to ensure your bottle always smells fresh and clean.

Properly clean your bottle regularly, store bottled water correctly, and avoid leaving stagnant drinking water at the bottom of the bottle. If the smell persists, even with thorough, regular cleaning, the best solution is to switch to a new bottle.


Why do plastic water bottles smell bad?

Plastic reusable bottles sometimes smell bad due to chemical leaching from the bottle materials, absorption of odors from previous beverages or other items in the bottle storage location, or bacterial growth due to stagnant water left in the bottle.

How do I stop my water bottle from smelling?

You can remove unpleasant odors and stop your bottle from smelling by ensuring the bottle is properly washed, allowing the bottle to air dry before putting it in storage, and only using the bottle to store clean water. You can soak the bottle in a baking soda or vinegar solution if the unpleasant smell lingers.

Why does my stainless steel water bottle smell bad?

Stainless steel water bottles may smell bad as a result of rusting bottle materials, residue from beverages, inadequate cleaning, and bacteria in the bottle.

Is it safe to drink from a water bottle that smells bad?

It’s usually safe to drink from a bad-smelling bottle, but we don’t recommend this because of the potential for bacteria in the bottle. Before drinking from the bottle, empty out the water, thoroughly clean the bottle, and add fresh water. If you can still smell an unpleasant odor, you may need to soak the bottle overnight.

What does mold smell like in a water bottle?

Mold has a musty, dirty smell in water bottles. The smell of mold is also described as “earthy” and “damp”. You might associate this smell with wet leaves and soil, or the smell of a damp basement or an area with poor ventilation.

  • Laura Shallcross
    Senior Editor

    Laura is a passionate residential water treatment journalist who holds an undergraduate degree in Print Journalism and a master’s degree in Creative Writing. Over a span of 5 years she's written on a range of topics including water softening, well water treatment, and purification processes.

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