How to Sanitize RV Water System

Here are the steps to sanitize RV fresh water tank and associated fresh water lines. Your RV’s fresh water tank and lines need to be sanitized at least once every six months. It should be part of every RV’s maintenance schedule. Sanitizing your RV’s fresh water tank and associated fresh water lines is easy – but it does take a little time. The most important thing is to wait the appropriate amount of time for the tank to be properly sanitized.

If you NEVER drink water out of your fresh water tank then you might think that you never have to sanitize it. However, if you use water from your fresh water tank for any purpose, and/or if you just want to make sure your water lines are sanitized, you should periodically sanitize RV fresh water system.

Here are the steps I take to sanitize RV fresh water tank and lines.

First, some things to consider before you start:

  • Time – I need at least 6 to 12 hours to complete the job.
  • Do you have internal and or external water filters? If so, you should change them after you have finished sanitizing the RV’s tank.
  • Do you have a hot water tank? If you do, now might be a good time to flush out your hot water tank (and while you’re at it, check to see if you need to change the anode).
  • Read through these sanitize RV instructional steps before you begin.

Step 1: Gather all the tools, and supplies you will need to sanitize RV fresh water system. For my RV I need:

  • 1 external water filter (from Walmart’s RV section)
  • 1 internal water filter – I use a Hydro life C-2063/#5 filter
  • Clorox® Regular-Bleach (non-scented and non-gel). Compute how much Clorox® you will need. I use 1 oz of Clorox® for every 8 gallons of water capacity in the fresh water tank.
  • 1 funnel with a flexible clear hose and stopper (from Walmart’s auto supply section)
  • 1 water filter wrench (for the internal filter)
  • 1 dab of petroleum jelly (for the O-ring on the water filter body)
  • 1 Anode if you need it and the tools to remove it

Step 2: Partially drain the fresh water tank to about ½ its capacity

Step 3: Prior to use, sanitize the funnel and hose with pure bleach. Let stand for 15 minutes, then discard the bleach in the funnel. Pour the Clorox® into the fresh water fill using the funnel with the flexible clear hose.

Step 4: Refill the fresh water tank until water starts coming out of the overflow hose or until you know it is full.

Step 5: Turn off the fresh water supply to the RV. Turn on your water pump so you will draw water from the fresh water tank.

Step 6: Open every faucet in the RV including the hot water faucet until you can smell Clorox®. When you can smell Clorox®, turn the faucets off. You might want to turn the power off to your hot water heater tank before you open the hot water faucets.

Step 7: Turn on the fresh water supply to the RV and add a few more gallons of fresh water to your fresh water tank. Now the waiting begins. For best results, wait a minimum of 3 to 4 hours to sanitize RV water system. I usually wait 6 hours.

Step 8: After the proper waiting interval, drain the fresh water tank until empty and refill with fresh water until full.

Step 9: Turn off the fresh water supply to the RV and turn on your water pump. Start flushing the water lines by opening all the faucets. Leave them open until the smell of Clorox® has diminished. If after a few minutes, the Clorox® smell is still too strong then drain the fresh water tank again and repeat step 8 and 9.

If the Clorox® smell still persists then you will have to get more aggressive. One option is to remove the old internal filter and repeating steps 8 and 9. A second option is to flush the system with a vinegar solution of 1 quart,vinegar to 5 gallons of water then repeat step 8 and 9. I have never had to do this, but I have heard from others who have.

Step 10: Turn off the water supply to the RV and remove the external filter, and replace with a new one. Make sure your water pump is off and replace the internal water filter with a fresh cartridge. Do not forget to dab a little petroleum jelly on the O-ring of the water filter body or you will have a hard time removing it next time you change the cartridge.

Step 11: I cannot go into much detail about flushing the hot water heater since there are so many different tanks and configurations however, see the brief overview below.

Turn power off to the hot water heater. Turn off the water to the RV and make sure your water pump is off. Open the relief valve on top of the water heater to expel any pressure in the hot water tank. Open the hot water heater tank drain valve and leave it open until all the water has drained out. Inspect and or replace the anode. Close the relief valve and the drain valve. Turn water to the RV back on again and refill the hot water heater. Check for leaks around the anode or the drain valve.

After you have refilled the hot water tank, make sure that all air is expelled from the hot water heater before you power it back up again or you will burn out the heating element. I do this by opening all the hot water faucets until no air comes out and I have a strong stream of water. When I am sure that all the air has been expelled from the hot water tank, I turn the power back on again to the hot water heater.

Where to Add the Bleach Mixture

Question: Where can I find the place to add my water/bleach mixture to sanitize the water lines in a 1998 gulfstream yellowstone fifth wheel?

Answer: You may have what is called a gravity fill opening. This is typically near the hose connection for the city water, often a larger opening so that you can pour in bleach in addition to filling it with water.

You may want to contact Gulfstream to see if you can get an owners manual for your RV, or ask them for instructions on sanitizing the water system for your specific configuration.

From the general owners manual we found online, it states that “Some models have a separate water fill for the FRESH WATER TANK. Others have a selector switch to select either LOCAL SUPPLY or FRESH WATER TANK. To use CITY WATER make sure the selector is set to LOCAL SUPPLY. The fresh water tank and water pump are by-passed when the city water hook-up is used.” So if you have a selector switch, you may need to set it to Fresh Water Tank while you are filling the tank.

We found that general owner’s manual at:

But you may want to call them to make sure you have the most accurate material for you model year fifth wheel. See