False: No matter what your parents told you, or what you see in the movies, there isn’t any magical chemical, that when added to a swimming pool, will reveal the presence of urine in the water.
Experts on such matters say that although a reliable dye could be produced, the trick would be getting it to react only to urine and not trigger in the presence of similar organic compounds that are likely found in most swimming pools.
It’s not a compound that anyone appears to be working on either, and with good reason – who’d want it? Kids are kids. Their reaction to the news that peeing in the pool would produce bright blue, purple or red trails would be to jump right in with the intent of putting that theory to the test. Especially in a public pool where anyone passing by can be can be blamed.
Chalk this belief up as what it is: yet another sneaky parent trick meant to keep kids in check. A similar “deterrent” rumor has to do with school fire alarms. This rumor warns kids that the school’s fire alarm switches are booby-trapped with a packet of red dye, that sprays upon whoever pulls the lever, marking him/her as the one who did the deed.