Better to wait until you see a fellow backpacker and ask for his local advice. Never, never smoke on the streets or beaches. Therefore, the hot water handle in your sink will have the letter C on it. The word for cold is Frio. The cold knob has the letter F on it.
Many tourists turn on the C for cold water in the shower and get a nasty surprise.
It often works. Well, I'm off to Zipolite. Hope I see you there, if not we'll communicate right here. The Great VavaVoom .