Every owner of an RV should keep the fresh water system sanitized. At a minimum, you should sanitize the system every spring when you take the RV out of storage and any time you notice an odor. It's really quite simple to do. You can start by draining the water heater. Go to the outside compartment where the water heater is located.
The drain plug, or petcock is located in the corner. Remove the plug and open the pressure relief valve on top of the water heater to assist in draining. CAUTION: NEVER drain the water heater when it's hot or under pressure.
You then need to locate the low point water line drains. It may take a while to find them, but they are there. There will be one for the hot and one for the cold water lines. This is the lowest point in the water system. Open these and let the water drain out. Next, find the drain for the fresh water holding tank and drain all of the water from it. At this point you can turn the water pump on for a moment to force any remaining water out. Do not let the pump continue to run once the water stops draining as it may be damaged. Close all of the drains. You have now drained most of the water from the RV's system.
Take a quarter cup of household bleach for every fifteen gallons of water that your fresh water tank holds. Mix the bleach, with water, into a one-gallon container and pour it into the fresh water holding tank. Fill the fresh water tank almost completely full of water. Turn the water pump on, open all hot and cold faucets and run the water until you smell the bleach at each faucet. Close the faucets. If it's possible drive the RV or pull the trailer so the water can move around to assist in cleaning the entire tank.
Let it sit for at least 12 hours. Drain the entire system again and re-fill the fresh water tank with potable water. Open all of the faucets and run the water until you no longer smell any bleach. It may be necessary to repeat this process again to eliminate all signs of bleach from the water system. Once this is done it is safe to use your water system.
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