Sanitizing Your Fresh Water Tank and Plumbing System

Many new RV owners do not realize that they need to sanitize their RV’s fresh water tank. This is the only way to ensure that you have safe RV drinking water before you set out on a road trip. If your RV has been in storage for a few weeks or months, you will likely have bacteria in your fresh water system. In order to make the water potable again, you need to sanitize your fresh water tank.

Even if you don’t usually drink water from your fresh water system you need to sanitize your fresh water tank and lines at least twice a year (every six months). You need to do it even more if you use the fresh water tank as a source for potable water. At the very least, you will be using this water for pets, for brushing your teeth and for washing up. Chances are you may use it for coffee and cooking, too, so it’s important not to skip this simple step.

If you haven’t been sanitizing your fresh water tank, you should make this a regular part of your RV maintenance checklist. Doing it doesn’t require much money, but it does require some time. In fact, you’ll need several hours for the fresh water tank to become sanitary. You should also sanitize your fresh water tank if you notice a sudden musty or stale odor from the water. Sanitize your fresh water tank again if there has been a boil water advisory or if you’ve had recurring issues with algae or slime.

Don’t skimp on changing the filter for your fresh water supply hose, too. They are important for removing sand, dust and rust. However, changing the filter does not substitute a good sanitizing session. Do both and drink safely!

If you are de-winterizing, preparing for the next season of camping, be sure to completely flush antifreeze from your fresh water system before starting the sanitation procedure! To flush antifreeze from your fresh water plumbing system fill your water tank and water pipes with clean potable water, then completely drain the tank and pipes of water at least once. It may be necessary to repeat this flushing precedure multiple times to deminish the lingering unpalatable aftertaste of some antifreezes.

Here are some quick steps to make sure your water source is clean and not a potential for disease. Read through the directions before starting this project. Also, keep in mind that you’ll need approximately 6 to 12 hours to finish the job.

What You’ll Need

• 1 New external water filter
• Fresh Water Supply Hose
• 1 Funnel with a flexible clear hose and stopper
• Chlorine bleach (unscented and non-gel); You will need approximately 1 oz. of bleach for every 8 gallons of water capacity
• 1 Hot Water Heater Anode (if necessary)

Directions

1. Drain the fresh water tank so that it’s only half full.
2. Sanitize the funnel and hose by filling it with a mixture of chlorine bleach and water. After 15 minutes, pour out the bleach mixture into the fresh water fill port  using the funnel with the flexible clear hose. Never pour straight bleach into the RV fresh water tank. 
3. If you have a bypass for the hot water tank, set it to normal use so the bleach mixture will circulate through the hot water tank. Make sure your hot water heater electric and gas switches are turned off.
4. Fill the fresh water tank until water flows from the overflow hose (that way you know it’s full).
5. Turn off the fresh water supply and turn on your water pump.
6. Turn off your hot water heater. Open all faucets (both hot and cold) in the RV until you smell bleach. Turn off the faucets when you smell bleach.
7. Turn on the fresh water supply again to top off your fresh water tank. Wait a minimum of 3 to 4 hours to sanitize the RV water system fully. Ideally, you should let it sit overnight.
8. Drain the fresh water tank and refill it with fresh water until it’s full.
9. Turn off the fresh water supply and turn on the water pump. Flush out the water lines by opening the faucets. Keep letting the water run until you no longer smell bleach. You may have to refill and rinse out the fresh water tank a second time if the smell of the bleach is still strong. If after a second rinse, you still smell bleach, you can flush the system with 1 quart of white vinegar and 5 gallons of water to rinse a third time. Some people prefer using a mixture of ½ cup of baking soda and a gallon of water in the fresh water tank until it flushes clean of bleach.
10. Turn off the water supply and water pump.
11. Flush the water heater next. The electric power should already be off to sanitize the fresh water system as described above, but double check that the electric power switch as gas is turned off.  Turn off the water and the water pump as well. Open the relief valve to the water heater (very important to prevent air pressure from building up and becoming combustible). Remove the hot water tank anode tube to drain all the water from the tank. You may need to replace the anode if it seems corroded. Close the relief valve and replace the anode - wrap the threads with plumbing pipe tape.
12. You are now ready to refill and turn on the water source to the RV. Make sure the air is completely expelled by opening all the hot water faucets until no air comes out and water is flowing steadily. When you’re sure it’s free of air, you can turn on the hot-water heater.

Your water source is now clean, fresh and ready for drinking!

This content is offered for informational purposes only and is not intended to replace manuals or instructions provided by the manufacturer or the advice of a qualified professional. No warranty or appropriateness for a specific purpose is expressed or implied.