Along with our keys, phone and wallet, water bottles have become an essential item that a lot of people can't leave the house without.
Psychology experts previously revealed that people had started carrying their reusable vessels for hydration around for 'emotional support', proving just how fond we have become of them.
So, this tidbit of information might pain you to hear - but if you aren't cleaning yours correctly, it could spell big trouble for your health.
It turns out that your beloved water bottle could actually be dirtier than your toilet seat if you aren't following the right procedure when washing it.
Scientists have warned that your canteen filled with H2O could be crawling with harmful bacteria, which might leave you feeling quite unwell.
The study
US filtration company WaterFilterGuru.com carried out a study to find out what germs are living in the containers which we sip water from all day, everyday.
Advert
They took three swabs from different kinds of water bottles - including spout lids, screw-tops, straw lids and squeeze tops - as well as a tap, to see what bacteria they found on each item.
The experts explained: "Researchers found two types of bacteria present: gram-negative rods and bacillus.
"Gram-negative bacteria can cause infections that are becoming increasingly resistant to antibiotics, while certain types of bacillus can lead to gastrointestinal issues."
The study found that the average reusable water bottle has a staggering amount of colony-forming units (CFUs), which is an estimate of how many living microbes there are in a sample.
Advert
It found that our trusty drinking flasks have up to 20.8million CFUs of bacteria - but spout and screw-top lids were even worse, with 30 million CFUs.
The tap that was tested also yielded the same result, while squeeze-top bottles were found to be the cleanest, with 3 million CFUs.
So, if the squeeze-top area of the shelf in the supermarket is empty, you know why.
'Filthier than your toilet seat'
Researchers then compared these bacteria stats to those of household objects to see whether reusable water bottles are filthier than our most commonly used items.
Advert
Spoiler alert, they are.
On average, a reusable water bottle has 40,000 times the bacteria of a toilet seat, according to the study. Grim, we know.
They also have 14 times more germs than a pet bowl and five times the amount of a computer mouse - so you really ought to triple check that you are cleaning your water bottle correctly.
Although you might have good intentions behind using a reusable bottle - such as protecting the planet and swerving the risk of microplastics - it could end up backfiring healthwise.
Advert
WaterFilterGuru.com found that a quarter of Americans only wash their bottles a few times each week, while over 10 percent of respondents admitted they only do it a few times each month.
Experts advise washing your water bottle thoroughly at least once a day and thankfully, there is also one on hand who has explained how to banish as much bacteria as you can.
How to keep your reusable water bottle clean
Dr Primrose Freestone, an associate professor in clinical microbiology at the University of Leicester, said you should clean your bottle with hot water which has a temperature of over 60°C.
Most pathogens can't survive this heat, so this is a great place to start - but a good dollop of detergent won't do any harm either.
Advert
She told BBC's Science Focus: "Add washing-up liquid, swirl it around and leave for ten minutes.
"Then rinse it with hot water and allow it to dry - overnight is best, as thorough drying will also help to protect against the growth of microbes.
"For more heavy contamination (from long usage without washing), add a half vinegar/half water mixture and soak for several days."
If you're following the formula for a deep clean, after it's done soaking, you should still give it a blast at over 60°C and follow the above method for good measure.
Offering some further advice, Dr Freestone added: "To avoid getting ill from your water bottle, you should ideally clean it with detergent after each use.
"It is also important to clean any lids or attachments such as straws as these can also harbour microbes."
The boffin explained that you might notice an 'odd taste or texture' when drinking from your water bottle if it is not clean.
"Any bacteria and moulds that may be present will grow and contaminate whatever liquid you put in it," she said.
"Then, when you next drink from your bottle, you may notice an odd taste or texture due to the waste products released by the growing microbes."
Stay safe, clean and hydrated out there, folks!
Olivia Burke