Why is underwear more disgusting than the bare body that it contains? It’s not like taking your underwear off makes you sterile no?
It is difficult to wash underwear with the same thoroughness. I have not seen people laundering their underwear before swimming.
[1] Our local pool changed to allow showering in one's bathing trunks. I personally don't like the rule, as I think people will skimp on washing their crotch before entering the pool.
For some reason most pools don't have the strong smell that I remember from my childhood anymore. Either it's because they are better ventilated, or because they check the chlorine levels more diligently (they sample the water every hour or so), or maybe I'm just not as sensitive to smells anymore.
There was even some neat research a few years back to figure out how much came from urea from pee, vs. from other bodily secretions: https://www.npr.org/sections/health-shots/2017/03/01/5177859... .
> The scientists calculated that one 220,000-gallon, commercial-size swimming pool contained almost 20 gallons of urine
After reading that NPR article, I can suggest another possible alternative; the pools might drain and refill their pools more often, rather than top-off when it gets low.
Dry hair might not be that good of an indicator? I mean, I see people doing breast stroke with their head completely out of the water.