I was in a college pool once that they said had a chemical it that turned red if you pissed in the pool...I didn't try to find out if it were true or not.
Back in the early 60's, a local company (mill) had an Olympic pool and diving tower built in their park. They were later forced by law to open it to all comers. A couple of years later they closed the park and dynamited the pool and tower. They couldn't keep the water in it at a safe level. (urine and feces floating in the pool)