Start with a nearly full tank of water. Top off the tank if necessary.
Dilute 1/2 cup of liquid chlorine bleach in one gallon of water for every 15 gallons of capacity in a clean bucket.
Pour the solution into the tank.
Fill the tank with water to the top and close it.
Open all faucets, one by one, inside the RV to on for 5 minutes to sanitize the entire system. Turn off all faucets.
Stir the solution around inside the tank by driving the RV for a short time. Allow the solution to sit in the tank for eight hours.
Drain the tank. Flush it with clean water until all the chlorine smell is gone. Fill it with clean water.
