But it's also a landing pad for germs that cause recreational water illnesses.
"Water illnesses are any type of infection such as diarrhea, which is the most common recreational water illness," said Dr. Elizabeth Duenas, with Kaiser Permanente. "It can also include pneumonia, ear infections, certain skin rashes among other things."
What if you accidentally swallow some of the water in a pool or pretty much any body of water?
"A lot of times, one gulp of this water can contain millions of germs that could make us sick," Duenas said.
Medical experts are not trying to discourage you from going swimming but you can take steps to prevent these illnesses.
There's a reason you're told to rinse off before jumping into a pool.
"Rinse off a lot of that dirt and sweat and oil and any possible fecal matter that may remain on our bodies."
The CDC also recommends looking at the water before getting in. It should be clear enough to see the drain in the deep end. If there's a line of scum or film around the pool, it might not be clean.
And if you've been sick, you should stay out of the water to protect others. If you have diarrhea or have had it within the last two weeks, you should not get in the water, Duenas says. Even if you feel OK, you may still carry the germs that can contaminate the pool.