So, the police are on standby to help the recreation department control the crowds and enforce the rules.
Residents looking for a cool off have to swim in shifts at the city pools when it's as crowded as it was on Thursday.
Capacity is dictated by how many lifeguards are on duty. It's 30 swimmers per lifeguard at the pools.
Once the pool is full, it's closed and the latecomers have to wait outside for a shift change.
"200, if that's the max, we have to stop, hold the rest of the folks at the gate, [then a] half hour, 45 minutes, hour later, they're allowed in, the other folks have to go," Deputy Mayor of the Environmental and Community Resources Michael DiBerardinis said.
The police help keep things under control.
On a day as hot as today, the wait outside seems unbearable.
Once they're in the water, the lifeguards have their hands full.
"It's hard, you really have to pay attention to the water," lifeguard China Bailey said.
Enforcing the rules isn't easy when this many people crowd into the pool at once.
There are frequent timeouts to go over the rules.
Most comply without a fuss, just to get back in the water as quickly as possible.
Parents appreciate the discipline.
"The lifeguards are pretty good here, they are really strict and stay on their of job," Sherrie Gaffney of Overbrook Park said.
It's elbow to elbow at times, but everyone does get a chance to cool off, even if it takes rotating shifts.
The police will remain stationed at some pools long after they're closed to prevent night time break-ins by kids trying to cool off.