Consult the maintenance guide that came with your RV. Locate the water heater in your RV and be sure that it is cool to the touch before proceeding. Locate and remove the drain plug and open the pressure relief valve. Locate and drain both the hot and cold low water lines by detaching them from the heater or by releasing the drain valves. Open the hot and cold taps attached to the sink of your RV and run the water pump for 10 seconds to ensure complete drainage of the water system. Turn off the pump and make sure all lines that you are opened are closed.
Make a mixture of a cup of bleach for each 15 gallons of water of the capacity of your holding tank -- for instance, a 30-gallon tank will need 2 cups of bleach -- in a large plastic bucket or plastic container. Pour the bleach mixture into your fresh water tank and then top off the tank with water. Turn on the water pump and open every faucet in your RV. Pay attention to the smell emitted from the faucets. Run water from the faucets until you smell bleach. Close all the faucets as soon as you smell bleach and allow the system to soak for 12 hours.
Drain the entire system once more. Refill the water tank and run water through the system until you not longer smell bleach. Once the smell of bleach has been eliminated, the water is safe to drink.
