Sanitizing Our Fresh Water System

How long has it been since you sanitized your fresh water system in your RV? Did you know your fresh water system needs to be sanitized on a regular basis? Even with a good filter, algae, debris, and bacteria can build up in the fresh water tank and plumbing.

The sanitation process can take several hours, and will require access to a fresh water supply.

We have a Keystone Laredo travel trailer with a 43 gallon fresh water tank, and our water cabinet includes the fresh water fill inlet, fresh water tank vent to prevent overfilling, valve for switching between onboard water and city water, black water flush inlet, outside shower port, and the cable TV connections.

View of the fresh water fill cabinet on our Keystone Laredo travel trailer

Close up view of the fresh water inlet connection and the fresh water tank vent

To sanitize a tank, use 1/2 cup of household bleach per one gallon of water solution to thoroughly sanitize our system. In order to add the sanitizing solution to our tank, I used a long funnel and the fresh water vent.

view of the bleach bottle i used to sanitize our fresh water system View of a long red funnel inserted into the fresh water tank vent

NOTE: The sanitizing solution needs to be something like Clorox regular bleach, where the active ingredient is sodium hypochlorite. It should not contain perfumes or dyes, and should not be labeled “chlorine-free.”

BONUS NOTE: Since you’ll be using bleach, make sure to wear old clothes, or that dingy white t-shirt you’ve been meaning to bleach. No matter how careful you are, bleach has a way of landing on your favorite black shorts.

After adding the sanitizing solution, I topped off the tank with fresh water, and used the water pump to flush the solution throughout the system until there is an odor of bleach coming from faucets (and don’t forget the toilets and showers).

Once the solution is in the system, wait about an hour. Bonus Pro Tips: You may want to turn on your exhaust fans, or sit outside while you wait! You may also want to put post-it notes on your faucets to remind people not to eat or wash with the tap water during this process.

After an hour has passed, drain the system using the drain on the tank. You should avoid using the water pump to drain a tank filled with sanitizing solution. The membranes in the pump can be damaged by long term exposure to the bleach solution.

You may need to check with your RV park to make sure they don’t mind you draining your fresh water tank at your site!

view of the fresh water tank drain with water flowing out

The fresh water tank will need to be filled and drained several times (at least twice) to rinse out the remaining bleach solution. Once the fresh water tank has been rinsed, use the pump to run water through all of the fixtures until the smell of bleach is gone.

If you happen to be battling a particularly stubborn algae problem, this process can be repeated.

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