No, you can't get pregnant from a swimming pool. Sperm ejaculated outside the human body likely only survive a few minutes. Ejaculate or seminal fluid dries out very quickly when outside the human body, once it is dried the sperm die almost immediately. Dissipated into pool water, a similar outcome would occur. About 200 - 500 million sperm are released with each ejaculation, and have the ability to swim about 8 inches an hour. Of these millions, less than 200 ever even make it into the uterus, and that is with the help of vaginal secretions and the motility of other sperm. Life of sperm increases once inside the female body and can actually live days in a fallopian tube waiting for an egg. Outside the body they're doomed!
If you are having sex in a pool it is possible to get pregnant. Please do not rely on the fact there is chlorine in the pool and that will “take care of the sperm,” that is not a good plan of action. If you’re just talking about going swimming, with no sex involved, then the answer is no. You can’t get pregnant.
Well when you consider the size of a sperm and the size of a swimming pool — talk about a little fish in a big pond. If you’re just worrying about going swimming and you aren’t the one engaged in sexual activity, then don’t worry about it. Having unprotected sex in a swimming pool won’t keep you from getting pregnant. But you certainly don’t need to worry about jumping into your neighborhood swimming pool and getting pregnant. Hope that clears things up a bit!