There are several ways to light RV water heater pilot conveniently. Before turning on the water heater in the pilot, make sure the tank is full of water, determine if your water heater is automatic or manual, Turn on the water heater's propane tank. Remove the control panel cover of the water heater to access the controls and buttons. Turn the control knob towards the pilot. Press and hold this button to feed propane through the lines, Hold this button for a few seconds or a minute until a spark through the pilot light appears. You can now set the water heater to the desired water temperature.