(well ANY pool really! but particularly ones that other people have to use)
i regularly go swimming and at my gym there are loads of signs everywhere asking that people shower BEFORE getting in the pool, and i always do, including my hair
but i always notice LOADS of people getting in dry who have blatantly not showered, and i can't believe the pool attendants don't say anything. (well they are probably not allowed
)
i know theres loads of chemicals and chlorine to kill germs etc but i still think its inconsiderate and gross not to shower before swimming.