A lot of us have a favourite water bottle and sip from it all day, every day.

I know this is true from working in an office. My colleagues and I continually use the same water bottles that sit on our desks each day.

But with the rise of young people becoming attached to their "emotional support water bottles" and the likes of trendy bottle brands such as Frank Green and Stanley dominating online shopping, maybe we should know how often our water bottles need to be cleaned.

This question recently came up in a group conversation and there were, quite worryingly, very different answers.

Someone I know said they haven't washed their new Frank Green bottle since they got it for Christmas and another admitted it had "been a few months" since they washed their water bottle properly.

You might think it doesn't need to be cleaned regularly, right? I mean, it's just water.

Some might say I'm a bit too thorough with cleaning in general, but my water bottle gets a proper clean at least once a week and a rinse every day.

But, how often should we really be cleaning our water bottles?

Last year, Sydney Water tested different water bottles for bacteria and found that washing a bottle once or twice a week in hot soapy water, or running it through the dishwasher, is the way to go.

Aussie Natural Spring water advises that water bottles should be washed daily.

In a recent article published in the American publication Health online, experts agree that water bottles need to be washed on a regular basis, but whether that's daily or every few days can vary depending on how often the bottle is used and how it's stored.

It's up for debate as to whether not washing water bottles often enough will make us sick, but it might cut back on the gross factor somewhat.

Ruby Pascoe

Senior Journalist