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How much pee is in the pool? Scientists use a sweet new test to find out

Admit it. Come on. Fess up. You’ve done it before, at least once in your life.

Maybe you were a just a child and you didn’t know better. But even pro athletes have copped to it.

Ahead of the London 2012 Olympics, Ryan Lochte reportedly said, “I think there’s just something about getting into chlorine water that you just automatically go”.

You may think but Lochte isn’t the best role model. After all, he did go on to trash a petrol station at the Rio 2016 Olympics. But even Michael Phelps – the guy with all the gold medals – agreed saying, “I think everybody pees in the pool. Chlorine kills it, so it’s not bad.”


“I peed in that pool four times”.

According to a survey conducted by the Water Quality and Health Council, one in five Americans admits to having peed in a swimming pool. The other four were probably liars.

Until now, we have had problems measuring just how much urine is in pools. This is primarily because healthy urine is about 95 percent water. So after you do the deed, poof, it’s gone. The perfect crime.

But now, finally, researchers from the University of Alberta have found a way to measure pool pee levels, and the results are not too good.

The researchers began by collecting 250 samples from 31 pools and hot tubs in two Canadian cities. They then analysed the water for traces of a sweetener called acesulfame potassium – Ace-K for short.

Ace-K was chosen because we ingest large amounts of it– it appears in diet sodas, candy and many other products – and then release 95 percent of it as urine.

The results of the research were published in the journal Environmental Science and Technology Letters. The researchers found that all of the samples had Ace-K in them, meaning that every single pool and hot tub was peed in.

They also calculated that in a pool containing about 415,000 litres of water, about 30 litres of that is pee. To put it in perspective, that’s 100 shot glasses. So if you have 50 swimmers in a pool, that’s two shot glasses per swimmer. Yikes!

In a larger 830,000 litre pool, the results were more than double, as they found around 70 litres on average (233 shot glasses to use the previous measure). This would suggest that the larger the pool, the more pee. Perhaps people think they can get away with it or that it matters less in a larger pool.

Chinese pool

Just imagine how much pee is in this Chinese swimming pool.

Then there is the hot tub, the preferred pool of middle-aged swingers and wannabe pickup artists. The study found that one hotel Jacuzzi had more than three times the concentration of Ace-K than the worst swimming pool. Think about that the next time you jump in one of those.

So is swimming in pee-laden pools actually dangerous?

Although mostly harmless, NPR reports that there is a potential health hazard. That’s because chlorine can react with urine to form a range of potentially toxic compounds called disinfection byproducts (DBPs). We’re not too sure about the effects of these DPBs, but they have been linked to eye and respiratory irritation. Long-term exposure has also been linked to asthma in pro swimmers and pool workers.

Although we now know how much urine is in a pool, we still don’t have a way to identify culprits. Until we can come up with that technology, pool peers will continue to go about their business under the cover of anonymity.

In the meantime, remember this, Pool Peers – just because it’s your pee, that doesn’t make it cleaner.

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