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Do you need to sanitize your RV fresh water tank?

As a new Airstream owner last year, this was one question (among many) that I forgot to ask while going through the final walk-through before I took my 23FB Flying Cloud Airstream home for the first time.

The follow up question would be how often and more importantly, how do you sanitize your RV fresh water tank?

Do you need to sanitize your fresh water tank?

The answer to the first question is pretty straight forward. You should sanitize your fresh water tank, even if you only use your fresh water for washing dishes and showering. Over time, you can still have some bacteria growth in the freshwater tank so proper cleaning and sanitizing will stop the bacteria.

How often should you sanitize your RV fresh water tank?

That answer is a little less clean. My Airstream owner’s guide only says:

Potable water systems require periodic maintenance to deliver a constant flow of fresh water. Depending on use and the environment the system is subject to, sanitizing is recommended prior to storage and before using the water system after a period of storage. Systems with new components, or ones that have been subject to contamination, should also be disinfected…

-My Airstream Owners Guide

So not very specific for someone like myself that is living in my Airstream full-time.

Fortunately, Vinnie at A to Z Motors, where I bought my Airstream, already had my Airstream’s water tank sanitized before I purchased it, so I was off the hook for a couple months.

I also usually stay hooked up to city water, so have only used the fresh water tank sparingly except for a couple trips to state and county campgrounds that had no hook-ups.

However, now that summer is rolling around and California is starting to lift its COVID-19 restrictions on non-essential travel, I’m looking at spending a few weeks towing my Airstream around the Eastern Sierras and maybe with a trip through Utah and Colorado to see a good college buddy in Boulder, I figure its time to make sure my Airstream fresh water tank is clean and full.

How to sanitize your fresh water tank?

So I started looking up the best way to clean and sanitize my Airstream’s water tank. Thankfully, the sanitization process is not difficult and is something you can start in the evening and then finish first thing in the morning.

How long does it take to sanitize an RV fresh water tank?

If you’re going to do anything right, getting your fresh water tank sanitized is probably something you want on that list! A bad GI bug or even worse, a case of Giardia, is not something I want as a summer Airstream camping memory this summer!

Airstream recommends AT LEAST 4 hours of contact time if you use their instructions for the normal fresh water tank sanitization solution.

Is there a quicker way to sanitize your fresh water tank?

However, if you double the bleach concentration, Airstream says you can cut the time the bleach and water solution needs to sit in the water tank and pipes by a whopping 75% or down to just one hour!

Equipment needs to sanitize your RV fresh water tank

The equipment needed for sanitization is pretty minimal.

  • Household chlorine bleach (no additives and unscented)
  • White RV water hose
  • Water filter
  • Measuring cup (1 or 2 cup size)
  • Funnel with bend in the spout

I use a funnel to make pouring the bleach into the fresh water opening easier, but its not necessary. I also make sure I have a water filter attached to my water hose to filter out any particular BEFORE it gets into the fresh water tank.

How much bleach do you need to sanitize your RV fresh water tank?

Airstream recommends using either of the two measurements for their regular 4 hour water tank sanitization:

Multiple the number of gallons capacity of your fresh water tank by 0.13. This number will give you the number of fluid ounces of bleach to use.

My Airstream Flying Cloud has 39-gallon fresh water tank, so I need to add 5 fluid ounces of bleach to a full 39-gallon tank.

Multiple the number of liters capacity of your fresh water tank by 1.0. That number will tell you the number of milliliters of bleach to add.

Since 1 gallon is equal to 3.785 liters (thank you Google!), my 39 gallons is also 147.6 liters. So I would use 147 milliliters of bleach.

Water Tank SizeConversion #Amount of Bleach
39 gallons0.135 ounces
147.6 liters1.0147.6 milliliters
How to calculate how much bleach to use based on your RV water tank size

If you want to speed things up and just spend one hour to sanitize your RV fresh water tank, just double the amount of bleach. So I would use 10 ounces or 294 ml of bleach to hurry up the process

Instructions on how to sanitize your RV fresh water tank

  1. Turn off your water heater AND fresh water pump.
  2. Unlock and open the door to the fresh water tank.
  3. Set up your RV water hose (and filter)
  4. Measure out the correct amount of household bleach in a measuring cup
  5. Add water from your fresh water hose into the cup with the bleach
  6. Use the funnel and pour the bleach and water mixture into the fresh water tank.
  7. Add clean water until your fresh water tank is full. There’s an overflow valve to the lower right of the fresh water tank inlet. When you see water coming out, your water tank is full!
  8. Turn on the water pump.
  9. Open up all the faucets and showers (DONT FORGET the outdoor shower!) and let the water run. I set the faucets to HOT so that water will flow thru the hot water heater as well.
  10. Once you can smell the bleach in the water coming out of the faucets and shower heads, turn off all the water.
  11. I will refill the fresh water tank at this point to be sure the bleach and water mixture is in contact with the entire fresh water tank.
  12. Let the water sit for at least 4 hours (unless you are doing the double concentration).
  13. After the 4 hours have passed, open up all the faucets and drain the fresh water tank until the bleach smell (and taste) is gone.
  14. Refill the fresh water tank with clean water.
  15. You’re done!

Can you sanitize your RV fresh water tank without bleach?

While doing the research for this article, I came across a couple of forum posts that mentioned alternatives to using bleach. There were a couple of natural solutions as well as one commercial product.

Natural ways to sanitize your RV fresh water tank

One alternative to bleach is white vinegar, however, one downside with using white vinegar is that its recommended to use a 1:1 ratio of vinegar to fresh water, so I would end up using almost 20 gallons of vinegar for my 39 gallon fresh water tank!

I would also imagine that much vinegar would leave behind a pretty harsh taste as well.

Baking soda was another non-bleach alternative for sanitizing an RV fresh water system. The one post I read on using baking soda recommend using 8 ounces (about 240 grams) of baking soda in one gallon of water However, I’m not convinced that the baking soda solution would be as effective as the bleach solution.

Commercial products to sanitize your RV water tank

I came across several commercial products to sanitize your RV fresh water tank.

Camco makes the TastePURE Spring Fresh Water System Cleaner for water tank cleaner and deodorizer. The solution comes in a 1 gallon container and is listed as safe for both RV and marine fresh water tanks. When I was researching, the Camco product had a 4.7 out of 5 star rating with 174 Amazon customer reviews.

A few people gave it 5 stars after using it when the bleach solution did not seem to fully clean their fresh water tank, so the Camco water cleaner may be something to try if the bleach and water solution doesn’t work for you

The Camco water cleaner isn’t a water additive since it contains ethyl alcohol (which is also used as a disinfectant) and sorbitan monooleate ethoxylate, which helps mix oils and water together.

Camco also makes the TastePURE drinking water freshener, which you can add to your fresh water tank and drink at the dilute concentration. This Camco product claims to take away any musty or unusual taste or odor in the water from the fresh water tank

Mistakes NOT TO MAKE when you sanitize your RV fresh water tank

Don’t rush the process! Let the bleach and water sit long enough to do its job – kill bacteria and sanitize the tank.

Use clean water! Make sure you’re using potable (drinkable) water when you sanitize the water tank.

Don’t use other cleaners except those listed in your Airstream owners manual or approved by Airstream. This means bleach and not Pine-sol or Mr Clean or some other disinfectant.

Don’t use ammonia with bleach!

When you mix ammonia and bleach together, it produces chloramine vapor which is toxic.

If you mix more ammonia than bleach, apparently you produce hydrazine, which can be explosive!

Here’s more complete info on why ammonia and bleach don’t make a couple that you want to invite along to your next campsite…

Don’t mix ammonia and bleach!

Other helpful tips about sanitizing your fresh water tank

When you’re sanitizing the fresh water tank, that’s probably also a good time to clean out the strainer in your water pump as well. The Airstream owners manual will tell you where your water pump is hidden.

For my 23FB Flying Cloud Airstream, the water pump is underneath the driver’s side closet. I just have to lift up the “floor” of the closet and I have access to the water pump. you can rinse out the strainer and look to see if the rubber O ring that acts as a seal for the strainer needs to be replaced as well.