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How to Sanitize Your RV Fresh Water System (Safe and Super Easy)

| Updated Mar 9, 2021

Here's how to sanitize your RV's fresh water system to stay healthy in your travels. Don’t worry, it’s easy! 

We can sometimes take clean water for granted, but when camping, we rely on our fresh water system for drinking and bathing. It’s important to remember that our RV’s fresh water system can become our main source of water for days at a time. 

Also, having a well-stocked and effective water system allows us to visit a larger variety of campsites that don't have hookups. 

Keeping the tank sanitized prevents our water from developing a strange taste or smell, or even worse, making us ill. 

When Should You Sanitize Your RV?

About every six months is ideal, even if you hardly ever use the water. But you may need to sanitize sooner if you sense a bad odor in the water, or after lending out your RV or buying a used RV

How to Sanitize Your RV Fresh Water System

Nothing can ruin a camping trip faster than discovering your only access to clean water is unsafe to use.

So, instead of driving back to civilization to buy gallons of water in plastic jugs, here’s how to properly sanitize your RV’s tank step by step (without hiring a professional! Which is certainly helpful when counting costs).

Before You Start

Carve out twelve hours to complete the process, and go to a location where plants won’t be harmed by being under your drain area. Turn off your water heater and let it cool. If you leave your water heater on while you drain you may risk damaging it. 

Next, gather your basic supplies of household bleach, a container such as a 1-gallon pitcher, a 1-cup measuring cup, a clean funnel, and a hose from a clean water source. 

Helpful tip: Wear clothes and shoes you don’t mind getting splashed with a little bleach just in case!

Next, turn off the water pump and icemaker if you have one. Also, if you have an external water filter, bypass it. Otherwise, bleach will go through it in the following steps. 

Draining the Tank (not just a fitness phrase!)

If your tank has unsafe, contaminated water inside, you will need to drain all the water, in which case it would help to keep your water pump turned on.

If the water is still clean, however, you only need to drain the tank about one-quarter or halfway.

To drain the tank, open the drain valve then tighten it again to stop.

Now the Bleach

How to Sanitize Your RV Fresh Water System (Safe and Super Easy) 1

You will not be pouring bleach directly into the tank, so first dilute it in water.

The general rule is one cup of bleach diluted in four gallons of water to sanitize a forty-gallon tank. Find out from your RV’s user manual the number of gallons your tank holds to calculate how much bleach you need to use. 

If you are using a one-gallon pitcher, add a quarter cup of bleach and fill the rest with water. In the scenario of a forty-gallon tank, you would need to fill this pitcher with that mixture four separate times.

Then pour this mixture into your fresh water tank using the funnel. 

Fill ‘Er Up with Clean Water

After adding the necessary amount of diluted bleach, grab your hose connected to a clean water source. Fill the remainder of the tank with water until it’s completely full. You’ll know for sure once you notice overflow appearing beneath the tank. 

Filling it all the way ensures you’re completely sanitizing because it's contacting every surface in your system with the diluted bleach.

Clean Out the Pipes

Next, turn your water pump on so the water can pass through the faucets and clean all the pipes out too.

Turn on every faucet in your RV one at a time to circulate this water through. Once you smell bleach coming out of the faucet, turn it off. This shouldn’t take more than a couple of minutes.

Note about hot water faucets: Some people don’t think it’s necessary to clean out the hot water faucets, but you can sanitize those too. If you want to, turn the water heater back on at this stage and run the hot water faucets until you smell bleach.

Since you used some water through the faucets, refill the tank until it is again overflowing.

Now, We Wait 

Allow this water to sit in the tank for a minimum of four hours, and a maximum of twelve.

This is the easiest step to sanitize your RV but takes the most patience. I recommend letting the water sanitize your RV on the longer end of time.  If you’re doing this process late in the day, you can let it sit overnight. 

Drain Again, and Again

After your sitting period is over, turn on the faucets and open the drain valve to empty the tank. Remembering to turn off the water heater in advance!

Refill your tank again with clean water and run the faucets until you no longer smell bleach coming out. 

If you still smell bleach after a few minutes of running the faucets, simply drain the entire tank again and refill. By doing this you are flushing the tank and completing the sanitization process throughout every nook and cranny of your RV. So, don’t get discouraged if you have to do this step a few times over.

Last Step to Sanitize Your RV Fresh Water System

After your tank is full of water without a scent of bleach, it’s time to finish up.

Turn on your water heater. You may have an external water filter to make better-tasting water (I use this one, which I replace every six months as well). To replace the old one, turn off your water supply and then install.

If you cleaned your water heater, read your manual for the correct way to refill it, as some manufacturers have different instructions.

If you followed all these steps, congratulations! You know how to sanitize your RV's fresh water system without hiring a professional! You are ready to camp with confidence that your water will be safe and reliable.

How Often Do You Sanitize Your RV?

Do you follow the 6-month rule of thumb? Or maybe even more often since the pandemic! Let us know in the comments and if you have any tricks you use to sanitize your RV. 

Photo of Mike and Jennifer, hosts of the RV Podcast
Mike and Jennifer, hosts of the RV Podcast

Curious about the gear, gadgets, accessories, and RV products Mike & Jennifer use and recommend?

On this RV Lifestyle Travel blog, our RV Podcast and our RV Lifestyle YouTube Channel, we mention all sorts of RV-related products and gear that we use, So we created a special page that links to them. We update this all the time.  CLICK HERE to go to it directly. 

Mike Wendland

Published on 2021-03-09

Mike Wendland is a multiple Emmy-award-winning Journalist, Podcaster, YouTuber, and Blogger, who has traveled with his wife, Jennifer, all over North America in an RV, sharing adventures and reviewing RV, Camping, Outdoor, Travel and Tech Gear for the past 12 years. They are leading industry experts in RV living and have written 18 travel books.

13 Responses to “How to Sanitize Your RV Fresh Water System (Safe and Super Easy)”

February 21, 2023at12:43 am, Mel Mulholland said:

There has got to be a better way to do this without wasting 40-80 gallons of water!

March 03, 2022at10:39 pm, Lorre Z said:

Is it necessary to sanitize the fresh water tank before first use? First time owner picking up new RV at the dealer next week. : )

August 07, 2021at11:34 am, Josef Graeber said:

My wife has a severe allergic reaction to bleach. Are there any other options that you would recommend.

April 03, 2021at9:58 am, Dr. Michael said:

I think you missed something-
What do you do if you have a clothes washer? If even the smallest amount of bleach remains, your clothes will be ruined.
Also, remember that bleach is a strong base and it will pit any metal (it really likes stainless steel!!) that it remains in contact with.

March 22, 2021at11:08 am, JMF said:

We have a 2019 Thor Siesta with an Anderson Kantleak water valve panel 200RV. The instructions are not clear about sanitizing the freshwater tank. We’ve found out that the “Sanitize/Winterize” setting ONLY sanitizes the fixtures and water lines, not the water tank as is stated in the provided basic operation guide. As there isn’t a separate freshwater fill, to sanitize the water tank, the valve needs to be turned to “FILL” and a hand pump used to pump the sanitizing solution into the freshwater tank. I found a cheap one at Camping World:
There is also an inline sanitizer which connects to hoses directly from Amazon which makes adding sanitizer easy:
Thought this might help some people.

March 30, 2021at11:51 am, Ken Duhm said:

For Anderson Valve users and others who do not have access to the fresh water tank, the hose can be filled with bleach – 50′ of 5/8″ hose will hold 1-1/2 to 2 cups – hooked up to water source and then run into fresh tank. The hot water system is just as important as the cold to sanitize. Water used for cooking is not always brought to a boil. You also shower (and ingest) with hot water so it too should be potable. A Winterize hook-up should not be used because it does not route water to the Fresh tank. The EPA has a standard method for sanitizing fresh water containers. This would be a good source to review if you update this article.

March 10, 2021at9:18 am, Ron said:

I have a 2019 LTV Wonder FTB. If I remember correctly there is no method of “pouring” water into the tank. You have to use the LTV system of sucking it up out of a bucket. Confirm please. If that’s the case, I need to get a 5 gallon bucket and designate it for fresh water only or use your one gallon method with the water pump 3.5 times. Obviously, I’ve not done this before and when I winterize I use the compressed air method since I’m in TX. My fresh water tank stays empty most of the time and is rarely used for drinking water.

March 21, 2021at6:29 pm, Tim Craig said:

LTV system ? I have no way of pouring water into tank either.

November 17, 2021at9:52 pm, Conrad Boucher said:

For the LTV you can get a collapsible 5 gal container so it is easily stored when not in use. It is a good way to fill the fresh water tanks when dry camping and not wanting to move to the water source in the same campground.

March 09, 2021at4:52 pm, Neal said:

Thanks for the refresher. It also is a good idea to check and clean the inlet strainer that many water pumps have. These trap debris and also can get algae in them (from my experience).

March 09, 2021at3:22 pm, Howard said:

My roadtreck is used 4-5 times a year. We live in the dry southwest desert. After each use the fresh water is drained and it sits empty till next use (could be months).
Is it necessary to sanitize the fresh water system if it is drained and empty between uses

March 09, 2021at10:19 pm, Mike Wendland said:

I would. There’s still bacteria that can get in.

March 09, 2021at9:25 am, Andy Cauthen said:

Thanks for the helpful information on sanitizing the fresh water tank. I’ll do that immediately when I get my Airstream out of winter storage. Then, we’re hitting the road!
Thank you.

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