How ‘clean’ are public swimming pools?

The spring flowers have all bloomed and the trees are finally lining the streets with their beautiful lush green leaves. Summer is just around the corner. And that means longer, warmer, sunnier days and spending time at your local Lido (or if you are fortunate enough, inside your own swimming pool).

There’s no doubt that swimming is a great form of exercise, but have you ever wondered how ‘clean’ the water is in your local public swimming pool?

Actually, let me first say this: But by no means do I want to eek you out and I know the topic I’m about to broach is not exactly dinner table conversation, but I’m just going to put it out there:

How much pee is in public swimming pools?

According to a recent news report, a typical swimming pool contains about 8 gallons of urine.

I know. Suddenly swimming does not sound that appealing anymore.

But it shouldn’t come as a surprise because according to this news report 1 in 5 Americans have admitted to peeing in a pool. A former Olympic swimmer even said that almost all competitive swimmers urinate in the pool.

Okay, just because Olympic swimmers do it, doesn’t make it any better. In fact, I think I might have put some of you off swimming for good (and that was not my intention. I promise).

So, the next question is: How safe is it?

Olympic legend Michael Phelps argues that pee in swimming pool water won’t do you any harm. That’s because of the chlorine levels. But the fact is, what you and I (and most other swimmers) associate with the smell of chlorine is actually the smell of disinfection by-products.

And, unfortunately, rather than being rendered harmless by chlorine, the uric acid found in human urine reacts with chlorine to form cyanogen chloride (CNCI) and trichloramine (NCI3).

Cyanogen chloride is actually used in chemical warfare and can be toxic to your lungs, heart, and central nervous system. Trichloramine is linked to lung damage.

I know, right? This sounds like scary stuff.

But don’t be alarmed, because the amount of CNCI and NCI3 found in a swimming pool as a result of human urine is negligible (something like 30 parts per billion) and that amount is well below the 70 ppb maximum cyanogen allowance in drinking water, according to the World Health Organization. Th damage to your health will only occur at much higher levels (about 2,500 ppb), an amount that would be difficult to generate from urination alone in a typical swimming pool.

In addition, urine isn’t the only culprit. Any organic matter — including hair, skin, sweat and dirt — can react with chlorine to create disinfection by-products.

Okay, that’s enough of the gory stuff. And again, I apologise if I dampened your enthusiasm about splashing around in the pool this summer.

Fortunately, you don’t have to give up swimming altogether. Swimming in the ocean or a lake are excellent alternatives. And if you want to swim on a regular basis and you don’t live close to the sea or a lake, find a gym with a saltwater swimming pool, which are kept clean from bacteria, algae and other organisms without the use of dangerous chemicals.

Finally, if you are using public swimming pools this summer lead by example. Don’t pee in the pool, teach your children and grandchildren to do the same and shower before and after using a chlorinated swimming pool.

To a healthier life,

Thomas Smith