Here's how much pee is really in a swimming pool

For all those water babies out there who have turned to heated pools in winter to compensate for missed beach swims, we hear you. But before you dive straight in we should probably warn you that there is definitely going to be wee in the water.

But exactly how much?

According to a recent survey by the Water Quality and Health Council about a fifth of people have admitted to peeing in a pool at least once. Bleugh!

Until now it’s been tricky to determine just how much urine those little ‘accidents’ are putting into the pool. And experts have warned that despite urine being sterile, certain compounds in urine have been found to react with disinfectants that can lead to eye and respiratory irritation. So, you know, its quite important we know how much wee we’re swimming in.

Thankfully though, researchers from the University of Alberta in Canada have managed to find a technique that allows them to estimate how much urine is in the water.

Samples are tested by looking at the levels of acesulfame potassium, an artificial sweeter that is often found in processed food.

If the water has higher levels of sweetener, it’s likely to contain a bigger concentration of urine

Scientists used this technique across 31 swimming pools and hot tubs in Canada in attempt to find out how much urine was floating around.

And if you’re a regular swimmer prepare to be slightly grossed out, as a total of 75 litres of wee was found over the course of three weeks.

Sounds a lot right? But before you refuse to ever dip so much as a toe in a public pool ever again, relax as that figure isn’t as bad as it might seem when you put the amount into perspective.

According to LiveScience, the study also revealed that the concentrations ranged from 30 nanograms per litre up to 7,110 ng/L, a variation that could be explained by factors such as how the pool water was filtered and how many people were swimming (and potentially peeing) in the pool. On average, the concentration of this artificial sweetener in pee is 4,000 nanograms per ML of water.

Using acesulfame potassium concentrations from the 22 pools and eight hot tubs as a guide, the researchers then collected 15 samples from two swimming pools over a three-week period. They estimated that a 220,000-gallon pool contained about 20 gallons (75L) of pee, and a 110,000-gallon pool contained about 8 gallons (30L) of pee.

Of course, 20 gallons of wee sounds like a pretty yucky amount, but in a 220,000-gallon pool, that’s only 0.01% of the total liquid in the pool — or in other words, a drop in the ocean.

Scientists also believe that, in the future, they might be able to use their sweetener test as a way to measure urine in pools to keep them at a hygienic level.

So though the thought of swimming in someone else’s pee might not fill you with joy, take heart in the thought that it’s likely a really small amount.

Nevertheless do please go to the loo before you jump in. You know it’s the right thing to do.

- Reporting by Marie Claire Dorking