First you need to drain and flush your black and gray water tanks. Then drain and flush your water heater. If a hose is not attached to the drain valve you need to attach one. After this please open any external faucets, valves and hose bibs for about thirty seconds. Next locate the pump and open any other external faucets. After this open internal faucets, showers, and toilets for about thirty seconds. Once done pouring antifreeze down the p-trap you are finished winterizing your RV water system.