HOW LONG DOES IT TAKE?

For a drink of water to be turned into urine: 25 minutes

‘THE liquid in a glass of water will enter the small intestine within ten minutes. From here it’s rapidly absorbed into the bloodstream and dilutes the blood,’ says Alan Doherty, a consultant urologist at Spire Parkway Hospital, Solihull.

‘If you have drunk water because you’re thirsty, the blood needs this dilution and you won’t make urine from that glass.

‘If the blood is already diluted, your body will send that water to the bladder within 15 minutes. The bladder can usually hold 400ml of urine before it needs to pass it.

‘On average you make around 100ml of urine an hour during the daytime and so only need to pass urine once every four hours.’