My roommate's hair stinks when her hair is wet. It is a sour smell, like milk when it's spilt and not cleaned up. She washes her hair every other day and it stinks everytime. She didn't have this problem until she moved and started using a different shower. But all of her hair doesn't stink, only a small section. She doubts it is her shampoo because she has used that kind for almost a year and never had this problem. Is it possible it is the water? But if so why does only part of it stinks? She also straightens her hair, is it possible she burnt a small section and that is why only a section stinks? After her hair is dry it smells good, like her shampoo.

HELP!!!