'Amy88' asked, 

Q. Can I get a bacterial infection or get a virus from a public swimming pool or waterpark?  They have to have chlorine so I should be safe, right?"

A. Regrettably, not all public pools and water parks get the sort of proper maintenance they require.  Poorly maintained swimming pools and other water parks may contain dangerous levels of bacteria, viruses, and parasites that, for some people, may result in ear infections, colds, pneumonia, stomach illnesses, 

Before you jump in, check to see whether the pool looks clean (you should be able to see the bot­tom), the pump and filtration equipment are working (you should hear them humming), and the pool walls should not feel slimy.

Many public pools have publicly displayed water test results on chalkboards or dry erase boards that also tell the time of the last test.  As a general rule, chlorine levels should be around 1 to 3 parts per million and the water should have a pH between 7.2 and 7.8 ppm.

So... if all chemicals are at the correct levels I'm OK, right?

Again, and most regrettably, not always.  Some strains of bacteria and types of viruses can withstand chlorine attacks and may linger in pool water longer than we'd like them to.  That is why swimmers are advised to stay out of the water if they have had diarrhea or gastrointestinal problems recently.

And it goes without saying that NO ONE SHOULD EVER PEE IN THE POOL!

Taylor K-1004 Troubleshooter Pool Test Kit