Is it clean and safe to swim in a pool after someone urinates it?

It is generally not recommended to swim in a pool after someone has urinated in it, as urine can introduce bacteria into the water which can cause health issues. Even small amounts of urine can result in the need to close a public pool in order to properly disinfect it.

Ideally, a person who needs to urinate should do so in a restroom facility designed for that purpose, and any pool users who suspect that someone has urinated in the pool should report it to a pool attendant or lifeguard so the water can be treated properly.