The wet, well-traveled floor is a campground for the dermatophyte fungus that causes athlete's foot. And just thinking of all those discarded Band-Aids gives us the willies. Wear rubber sandals in the shower. If your soap slides into a rarely cleaned corner, leave it for the janitor. As if the air jets tickling your backside weren't bad enough, you also have to worry about pseudomonas, which thrives in warm water and causes skin infections, particularly around hair follicles.
Hot tubs can also harbor chlamydia, which can cause eye infections.
Foam is a sign of an unclean hot tub. Even if it looks clean, dunk a clear glass into the tub and inspect the water, advises Eickhoff. If it's cloudy or discolored, stay out. And don't drink it. If they have to be in day care, find a provider who separates the incontinent tykes from the older kids.