There are several different illnesses you can get from swimming in contaminated water such as diarrhea eye, ear, skin, and respiratory infections. These are coming from germs in the water. To make sure that you are not spreading these germs: always shower before entering a pool; don’t go swimming when you have diarrhea; deposit your bodily wastes in the toilet instead of the pool; wash your hands after using the toilet; don’t swallow any water you swim in; and so on. The germs that are on you will get in the water, the same as everyone's around you! So to stay healthy, stay clean.
Positive Tip: Showering before and after swimming is to protect you and others from waterborne illness