We all know the biggest reason you shouldn’t pee in the pool ‘ it’s gross! But it turns out that there’s also a health-related reason not to. According to a study in the American Chemical Society’s journal Environmental Science & Technology, potentially harmful compounds are created when urine and chlorine mix. One common compound, called trichloramine, is associated with lung problems. A second compound, called cyanogen chloride, can affect the lungs, as well as the heart and central nervous system. Even if you think the pool you’re swimming in is clean, err on the side of caution and keep your mouth closed under water.
As for whether it’s safe to pee in the lake or ocean; The jury’s still out on that one.