A tankless water heater for RV includes a heat exchanger disposed in a housing with an inlet cold water line and an outlet hot water line extending outside a front side of the housing. A burner, disposed in an operative relationship with the heat exchanger, is provided for heating water flowing through the heat exchanger and an exhaust system induces is provided to move exhaust fumes out a vent duct. The tankless water heater for RV can be partially automated using a microprocessor, which can receive signals from various sensors mounted with the water heater and can send control signals to control one or more parameters.