Millions of adults are consuming less water than the recommended daily allowance – with one in 10 admitting they never drink it.
Research into the drinking habits of the nation found the average adult drinks around one litre of water each day.
But guidelines from health experts say the optimal amount is closer to two or three litres daily.
The study of 2,000 Brits found exactly half have no idea how much water they should be taking on.
And of those who understand how much they need, 39 per cent confess they only have the recommended daily allowance of water ‘once in a blue moon’.
A spokesperson from Zip Water, which commissioned the study, said: “Hydration is so important, but it’s very easy to let it slide.
“The goal is to never feel thirsty – if you feel like you really need some water, you’ve probably already left it slightly too late.
“A great way to help is to have a water bottle on you at all times, it’s very easy to regularly have a sip if it’s always nearby.”
Of those who don’t drink enough H2O, 10 per cent feel anxious when they haven’t got enough, and 14 per cent are easily irritated.
More than one in three feel sluggish and tired (both 34 per cent), while 18 per cent find it difficult to focus and a further 15 per cent get a bit weak.
And 11 per cent admitted to feeling distracted when not getting enough fluid on board.
The main reasons for avoiding drinking water are not liking it from the tap (27 per cent), disliking the taste in general (24 per cent), and finding it boring (25 per cent).
As many as four in 10, however, simply prefer drinking other things, with 35 per cent of all adults saying they drink tea and coffee more than anything else.
As a result, 46 per cent get nagged by others for not taking on enough water, according to the figures by One Poll.
To try and up their intake, 30 per cent do keep a water bottle handy to sip from throughout the day, and 29 per cent glug some first thing in the morning.
Nearly three in 10 (28 per cent) will keep a glass near their bed so it’s handy to have after a night out, to attempt some last-minute rehydration.
More than half of water drinkers (57 per cent) buy bottled drinking water, spending an average of £5.70 a month on the luxury.
Zip Water’s spokesperson added: “We’re very fortunate in the UK that our tap water is absolutely fine to drink.
“Filtered water is a great way of giving people peace of mind their water isn’t dirty, or even full of microplastics or chlorine.
“The most important thing, ahead of taste, is hydration and making sure your body has all it needs to function most efficiently, where water is absolutely vital.”
