Human feces taint more than half of swimming pools says CDC study

[DRoseDARs]

22. Patrons. Don't. Shower.

It's as simple as that in many cases. I'm a CPO responsible for maintaining both a lap pool and a spa, and I cannot tell you how many people flat-out ignore the signs we have posted everywhere to shower before they get into either. Often times they come straight from the locker rooms, even straight from working out or attending a class (like Spin Bike classes *shudder*). Some even go straight from the sauna with their sweat. Before you get indignant at the establishments, watch your fellow patrons and politely ask that they make sure they shower before bringing any of their ooly-goolies in with them.

Pool maintenance is an art, not a science, due to the wildly uncontrollable variable of patrons abusing their stay.