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How to Clean a Hydro Flask: Like a Pro

Here are six easy ways to clean your Hydro Flask.

A Hydro Flask is brilliant in many ways: it keeps cold drinks cold and hot drinks hot. But it’s not yet self-cleaning, so you need to know how to clean it to avoid stains, odors, and bacteria.

Thankfully there are many ways to clean a hydro flask. We’ve got six easy methods to share with you today using products you probably already have in the house.

Keep reading for our step-by-step washing instructions for how to clean a Hydro Flask and keep it fresh.

Key Takeaways

  • Clean your Hydro Flask after each use with warm soapy water and a bottle brush to prevent stains, odors, and bacteria.
  • For deep cleaning, use distilled white vinegar to remove odors, mold, and stains by filling the flask with ½ cup of vinegar and letting it sit for five minutes before scrubbing.
  • Certain Hydro Flask lids and straws are dishwasher-safe, but avoid putting the flask itself in the dishwasher to prevent damage to insulation and powder coating.
  • To maintain your Hydro Flask, avoid using harsh chemicals, soaking it for too long, and exposing it to extreme temperatures.

How Often Should a Hydro Flask Be Washed?

Ideally, you should wash your Hydro Flask after every use. Warm water and dish soap are enough to keep it clean on a daily basis.

As for deeper cleaning to remove stains, fight bacteria and tackle odors, once a week is enough.

If you don’t wash your Hydro Flask regularly, you could be dealing with:

  • Bacteria: Bacteria builds up in moist, warm places — like water bottles. You don’t want to be drinking potentially harmful bacteria.
  • An ugly water bottle: The last thing you want is for your Hydro Flask to look and feel dirty.
  • Odors: If you don’t keep the flask clean, it will stink whenever you open it.
  • Mold: Mold easily and quickly grows in water bottles, especially around the seals. Keep on top of cleaning to avoid and eliminate mold.

Can I Put My Hydro Flask In the Dishwasher?

You cannot put the whole Hydro Flask in the dishwasher, but certain lids and straws are dishwasher-safe. This includes the Hydro Flip Lid, Sports Cap, and Wide Straw Lid. The Flex Cap, Wide Flat Cap, Stainless Steel Flat Cap, and Loop Caps aren’t dishwasher safe.

Just keep in mind that the dishwasher temperatures can damage the flask’s insulation and powder coating.

How to Clean a Hydro Flask

Let’s look at six great methods to try. Each of these will deep clean your Hydro Flask, and tackle mold, bacteria, stains, and odors. Some might be more effective or easier than others, but it’s up to you which one you go for.

With Soap and Water

You should clean your Hydro Flask with soap and water after each use. Doing this daily will prevent bacteria, mold, odors, and stains. So if you do this regularly, you should never have a problem with your flask.

  1. Prepare the sink: Fill the sink with hot water and dish soap.
  2. Add Hydro Flask: Take apart the lid and straw from the bottle and add all three parts to the soapy water.
  3. Scrub: Use a bottle brush to scrub the flask well. This will allow you to reach the bottom of the flask. Scrub the other parts with a sponge or dish cloth.
  4. Clean drinking spouts: Bacteria and mold love to fester in small areas like drinking spouts. Scrub the drinking spouts clean with a small bottle brush or teat brush. If you have a pipe cleaner, you can use this instead. Don’t forget to scrub the inside of the straw, too.
  5. Rinse: Rinse each part with warm water.
  6. Dry: Leave the pieces on a drying rack upside down to drip dry. If you need to use the bottle right away, quickly wipe it with a dish towel and reassemble it.


Don’t soak the bottle in warm soapy water, even if it’s really dirty. Prolonged exposure to soap can damage the insulation.

With Baking Soda

Baking soda is a great natural cleaner. When you use it as a paste, it’s amazing at tackling stubborn stains and odors.

  1. Create a paste: In a small bowl, combine two tablespoons of baking soda with two tablespoons of water. Mix well.
  2. Apply paste: Use a cloth or an old toothbrush to apply the paste to stains. This is particularly useful for the outside of the flask. However, you can also apply the paste to any other part of the bottle — it’s super handy in crevices and threads.
  3. Scrub: After 10 minutes, scrub the baking soda in with your cloth or toothbrush, rubbing until the stain lifts.
  4. Rinse: Rinse the Hydro Flask under warm water.
  5. Dry: Let the flask drip dry on a drying rack.

With Vinegar

Vinegar can kill mold and remove odors. If you’ve neglected cleaning your Hydro Flask for a few weeks, this can rejuvenate it. It’s also great to sanitize your flask since vinegar can kill mold.

  1. Add vinegar: Pour ½ cup of distilled white vinegar into the Hydro Flask. Put the lid on and shake it well.
  2. Soak: Let the vinegar soak inside for five minutes.
  3. Scrub: Use a bottle brush to scrub the inside and bottom of the flask well. Use a cloth to wipe the inside of the lid.
  4. Rinse: Pour the vinegar out and rinse the Hydro Flask with warm water.
  5. Dry: Let the flask dry on a drying rack.

With Lemon Juice

When life gives you lemons, clean your Hydro Flask. This is great for removing stains and odors. It’s primarily used for the interior of the Hydro Flask, since the acid in the lemons could potentially damage the exterior coating.

  1. Squeeze a lemon: Squeeze half a lemon into the flask.
  2. Add water: Add ½ cup of boiling water to the flask, close the lid and swish it around.
  3. Wait: Give the lemon and water 5-10 minutes to soak.
  4. Scrub: Use a bottle brush to scrub the inside of the flask. Wipe the lid, straw, and spout down with a cloth.
  5. Rinse: Pour out the lemon water and rinse the flask well.
  6. Dry: Let the flask drip dry on a drying rack.

With Boiling Water

This is an excellent option for daily cleaning if you want to tackle bacteria that might be lurking in the bottle. You can do this quickly after using soap and water.

  1. Boil water: Boil some water in a kettle or on a stove.
  2. Pour: Pour the boiling water into your Hydro Flask, put the lid on, and swirl it around.
  3. Wait: Wait 5-10 minutes for the boiling water to do its work to disinfect the bottle.
  4. Rinse: Rinse out the Hydro Flask with warm water.
  5. Dry: Leave the Hydro Flask to drip dry on a drying rack.

With Denture Tablets

If you’re looking for a fun hack worth a go, you can try cleaning your Hydro Flask with denture tablets. These can remove stains like magic — no effort required.

  1. Fill bottle: Fill your bottle with lukewarm water.
  2. Add tablet: Add one tablet to the water.
  3. Wait: After five minutes, shake the bottle well. Wait another five minutes before emptying the water.
  4. Rinse: Empty the water and rinse the bottle really well. You may want to scrub with dish soap to remove denture tablet residue.
  5. Dry: Leave the Hydro Flask to drip dry on a drying rack.

Top Tip

For really filthy Hydro Flasks, you can leave the denture tablet inside the bottle for up to 30 minutes.

Tips For Caring For a Hydro Flask

We’ve shown you how to wash a Hydro Flask, and it’s super easy. But how do you care for one and keep it in mint condition? Here are our top tips:

  • No harsh chemicals: Keep it simple when cleaning a Hydro Flask. Avoid harsh chemicals like bleach, which can cause damage, discoloration, and rust.
  • No intense heat: Don’t put your Hydro Flask on or near a stove, microwave, oven, or dishwasher.
  • Store properly: When storing the Hydro Flask, keep the lid in a separate place or loosely screwed it on. This allows air circulation and prevents mold and bacteria growth.
  • Don’t soak it: Even if it’s really dirty, don’t soak it in water for longer than 10 minutes. This can discolor the exterior powder coating.
  • No freezing: Don’t put your Hydro Flask in the freezer. First, it won’t freeze due to the insulation; secondly, the temperatures can damage the flask.
  • Avoid the dishwasher for certain caps: Certain caps can’t go through the dishwasher. Hydro Flask advises against putting the Flex Cap, Wide Flat Cap, Stainless Steel Flat Cap, or Loop Caps through the dishwasher as they can harbor water which can lead to mold. On the other hand, the Hydro Flip Lid, Sports Cap, and Wide Straw Lid are dishwasher safe but on the top rack only.
  • Clean lid gasket: The lid gasket is the small rubber loop that seals the lid to the bottle. You can remove this and clean it. This will allow you to clean underneath it and tackle mold and bacteria.


How Long Does a Hydro Flask Last?

With proper care, you should get around 10 years of use from your Hydro Flask. But we have some amazing news: Hydro Flask offers a 100-year warranty! So if anything goes wrong with your Hydro Flask, you’re covered for life.

What Can You Not Put In a Hydro Flask?

You can put almost any drink into a Hydro Flask. But there are some things you shouldn’t store in a Hydro Flask, especially for an extended period of time.

  • Lemon Water: The lemon juice can rust the inside of the bottle after a prolonged period of time.
  • Milk: When milk is stored in the flask for a long time, microorganisms can grow. Milk should be kept refrigerated so that it doesn’t spoil.
  • Bleach: Don’t store bleach or chlorine in the Hydro Flask — this will damage the interior.

Can a Hydro Flask Rust?

Yes — stainless steel is rust-resistant, but that doesn’t mean it’s rust-proof. When stainless steel is exposed to water for a long time, it can rust. Bleach can also cause the Hydro Flask to rust, as well as salt water and high heat (like that from a stove, microwave, or dishwasher).

Keep your Hydro Flask clean and let it fully dry occasionally. If you notice rust, remove it with our vinegar or baking soda trick.

Remember that if you can’t remove the rust, you’re covered by a 100-year warranty.

How Do You Clean a Hydro Flask With Stickers?

Many people personalize their Hydro Flasks with stickers. Undoubtedly, this makes it a bit harder to clean since warm water and soap can destroy the stickers. We recommend choosing high-quality, waterproof stickers.

Wash your Hydro Flask as normal with warm soapy water and replace the stickers when needed.

How Do You Get Rid of the Smell in a Hydro Flask?

Using the distilled white vinegar hack will tackle odors and keep your flask smelling fresh. Simply fill the flask with ½ cup of distilled white vinegar, put the lid on, and swirl it around. Let it soak for five minutes before scrubbing well.

Rinse and air dry.

How Do You Get the Metallic Taste Out of a Hydro Flask?

If you don’t clean your Hydro Flask after each use, bacteria can build up. This bacteria can corrode the stainless steel, bringing out the metallic taste. Rust can also make your Hydro Flask taste metallic.

To remove this metallic taste, you can try filling the flask with a 1:1 ratio of distilled white vinegar and water. Leave it to soak for 24 hours before rinsing well. Leave the bottle to air dry fully.

If it continues to taste metallic, contact Hydro Flask and submit a warranty claim.

The Best Cleaning Methods

You should clean your Hydro Flask with warm soapy water after each use. This will keep mold, bacteria, odors, and stains at bay.

If you have further issues with your flask, you can try another one of our methods. For instance, vinegar will help remove odors and mold. Lemon juice is great for removing stains.

Always use a bottle brush to scrub your Hydro Flask and remove gunk from the inside and bottom. Don’t forget to avoid the dishwasher, high heat, and storing milk in your Hydro Flask for long periods!

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About the Author

Beth McCallum

Beth McCallum is a freelance writer & book blogger with a degree in creative writing, journalism, and English literature. Beth firmly believes that a tidy house is a tidy mind. She is always looking for new ways to sustainably clean and tidy her house, that's kind on the environment but effective in the house, too!