hydster is correct -- "hot tub folliculitits" is a common skin rash caused by bacteria that are found in hot tubs, even in ones that are well-maintained. But, while a nuisance , it's not a serious infection and in most cases is self-limited (ie - resolves on it's own with no specific treatment). And it seems that the rash is more common when people stay in for extended periods of time. The other common infection from hot tubs is a swimmer's ear -- caused by the same bacteria as the rash but unlike the rash, swimmer's ear can be painful and does requires treatment with antibiotic ear drops. Both these infections (rash and ear) can come from regular pool water too but the warmer temp of the hot tub increases the risk. So, as a physician, my advice to my patients and my own family is that, if you are in overall good health, brief periods of time in a hot tub (10-15 min.) are OK but whatever you do DON'T put your head under!