15 May 2026
Water bottle cleaning cheat sheet:
- Wash your water bottle daily if you use it every day
- Warm water and Washing Up Liquid does most of the heavy lifting
- Lids, straws and seals are where bacteria love to hide
- Let bottles air-dry fully before reassembling
- If it smells weird… clean it!
That reusable water bottle we sip happily from all day?
It’s working hard, saving us from single-use plastic bottles of water. But all-the-while collecting bacteria along the way.
The good news is… it’s easy to keep it clean once you know how.
So, what’s inside a reusable water bottle?
If it’s just filled with water, why would it get dirty?
Reusable water bottles are damp, warm places that offer five-star accommodation for bacteria. Over time, bottles can contain:
- Bacteria from saliva (we all have hundreds of species in our mouths)
- Germs transferred from hands and surfaces
- Biofilm (a slimy bacterial layer that sticks to the inside)
Studies have actually found bacteria levels can rise into the millions per millilitre within a day¹ . Eeek.
Can the bacteria affect us?
Luckily most bacteria are harmless and your immune system should sort them out.
But it’s worth remembering that some bacteria can cause stomach upsets and any mould or fungi can be triggers for people with allergies.
So while there’s no strong evidence linking reusable water bottles to serious illness outbreaks, cleaning your bottle properly is very much about good hygiene.
Which all means a quick cold water rinse doesn’t cut it.
How often should you wash your water bottle?
- If you use it every day, then daily.
- If it contained liquid other than water, then after every use.
- At the bare minimum when just drinking water, wash it several times a week.
- If it smells weird, looks cloudy or feels slippery inside - clean it sooner!
How to clean a water bottle properly.
For an everyday clean.
- Take the bottle fully apart (including any lids or straws)
- Fill with warm water and a few drops of Washing Up Liquid
- Scrub the inside with a bottle brush
- Wash any lids or straws separately
- Rinse thoroughly
- Leave everything to air-dry completely
And the drying bit is important, remember bacteria LOVE moisture.
For a deep clean.
- Option 1. Add 2 teaspoons bicarbonate of soda to warm water. Leave overnight before rinsing well.
- Option 2. Fill the bottle one quarter full with clear vinegar. Top up with warm water and leave for half an hour. Rinse well.
How to clean a metal water bottle.
Metal bottles are usually easier to keep fresh. They’re less likely to hold onto smells but they still need regular cleaning.
- Wash as normal with warm water and Washing Up Liquid
- Use a brush to reach the base and sides
- Avoid abrasive cleaners as they could scratch the surface
- Dry fully
What material is best for refillable drinks bottles?
From a hygiene point of view the best options are:
- Stainless steel. It’s durable and doesn’t hold smells easily
- Glass. It’s non-porous and easy to clean (but breakable)
- Bottles with wide openings and no fiddly seals or straws.
Cleaning refillable drinks bottles FAQs.
¹ Rapid Microbial Growth in Reusable Drinking Water Bottles. Quishan Lui. 2017
Catherine Green, Cleaning Expert
Catherine has been on a mission to revolutionise the way we tackle chores since the dawn of smol and is an advocate for making more sustainable living accessible to all, with a strong focus in cleaning that’s heavy on dirt, lighter on the planet. Catherine has tested hundreds of hacks to make tackling chores easier, safer, and better for the planet and our homes.
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