There is no such thing as a "洗身房" in mainstream Cantonese. We would say "厕所" or "洗手间". "厕所" refers to the place for excretion, and "洗手间" refers to the room where hands are washed, which is a relatively implicit term. But the meaning of the two is the same

廁所 means toilet and most of the time there are the toilet and shower in one room so we could also called it bathroom 浴室 洗身房 literally means a room to wash the body but it seems a bit strange to use this word as very seldom to see it. Maybe it was supposed to be 洗衣房 / 洗衫房( laundry room) ?

I don't really use chung1leung4fong2 cos the shower or bathtub are already included in 廁所