As an Amazon Associate we earn from qualifying purchases made on our website. If you make a purchase through links from this website, we receive a small commission from Amazon and other similar affiliate programs at no extra cost to you. You can read our complete legal information for more details.

Do I Need To Sanitize My RV Fresh Water System? What You Need To Know

Woman washing dishes in RV sink

Most RVs these days have a few different water tanks to keep contents separate from one another. Gray water, black water, and fresh water systems are the most common. When you live in a house, the fresh water gets filtered and sanitized before coming out of the faucet. However, you might be surprised about the cleanliness of an RV fresh water tank.

You need to sanitize your RV fresh water system because mold, bacteria, and sediment can build up over time. A mixture of water and bleach or a sanitizing product is required to clean the tank whether or not it looks dirty. Clean the RV fresh water system regularly to prevent unwanted contamination.

Throughout this post, you’ll also learn additional information about RV fresh water tanks, including:

  • What they are
  • Why you should sanitize them regularly
  • How to clean them
  • Different products to consider
  • How often you need to clean the whole system

What Is an RV Fresh Water System?

RV fresh water tanks are essential for a variety of daily uses. Without this system, you wouldn’t be able to partake in most creature comforts and necessities that motorhomes provide. Fresh water tanks contain clean, potable water that you can use while camping or while on the road vacationing.

The fresh water system is propelled by a water pump that usually sits underneath the main bed, under the table, or in a cabinet. It pulls the water from the fresh water tank through a series of pipes. Depending on which source you’re turning on, the correct valves will open correspondingly.

Note: The water pump uses a bit of electricity. Make sure the battery (or batteries) in your RV are charged before using any water source. Most RVs have a meter that allows you to check the water pump, batteries, water tank capacity, and more.

Let’s check out the three primary purposes of an RV’s fresh water system below.

  1. Drinking water is probably the most useful reason to clean the fresh water system. Having a method that provides potable water while you are camping comes in handy. You can use this water to make your favorite drinks, food, or just to have a refreshing drink of water after a hot day on the hiking trails.
  2. Another great feature of a fresh water tank is that you can use it to take showers. Having clean bathing water is hard to come by when you’re out in the middle of the woods. Unlike tent campers, you’ll be able to take a quick, warm shower every morning before starting your day.
  3. Fresh water comes through the sinks in the kitchen and bathroom. You can then use this water to wash your hands, clean the dishes, or do the laundry. There are lots of other uses for fresh water from the sink as well. As long as you have sanitized it, you’ll be able to use it as often as you’d like.

Other Posts of Interest

Why Do I Need to Sanitize the Fresh Water System?

When you’re relaxing at home, you might not know it, but you have the luxury of pre-filtered and sanitized water. It usually comes from a local lake or river then goes through a treatment plant. The treatment plant often adds minerals and also removes pollutants.

Once it arrives at your sink, shower, toilet, or garden hose, it should be suitable for all your potable water purposes. You may even have a filter in your house to filter out even more things, like sediment, chlorine taste, and more.

You can get sick from bacterial growth if you don’t sanitize your fresh water system. It can also cause the water to taste gross, which can influence the flavor of drinks and get onto your dishes. Not only that, but stagnant water starts to get stale after a couple of weeks or months.

The simplicity of an RV potable water tank doesn’t include enough filtration, unfortunately. You’ll need to sanitize the water yourself. Many experts recommend removing all of the water from previous trips before you hit the road on a new adventure. Cleaning it out and adding fresh, potable water is the best approach.

Another reason that you need to sanitize the water tank is that it’s effortless to access. Whether you’re worried about animals, kids, or even a loose cap, the water tank doesn’t have many protective barriers in the way. Some RVs have keys to access the fresh water tank, but old models only have a twist cap.

If you forget to seal the lid or someone else loosens it, you could end up with contaminated water. To avoid sickness or foul-tasting water, follow the suggestion mentioned earlier of cleaning it regularly. Peace of mind is priceless, and besides, the sanitization cost is close to nothing as well.

What Products Are Available?

Cleaning your motorhome’s fresh water system isn’t all about focusing on the tank itself. There are other components that you need to think about also.

Before we get into what to use and how to sanitize the system, here are a few other factors to consider:

  • When filling your fresh water tank, use a hose specifically made for potable water use, don’t use a regular garden hose. Potable water hoses are usually white.
  • Water heater tank rinsers are another option that you might want to employ before you start the sanitizing process. They’re designed to remove the debris that sticks to the tank. You can hook it to a hose and channel the water pressure to help remove sediment and prolong your heater’s life.
  • Purchase replacement water filter cartridges or install internal water filters in your RV.

Another great suggestion is to use external water filters. These can be hooked up to the system, removing sediment that settles in water tanks that aren’t used regularly. The residue contains calcium and other minerals naturally found in water. By filtering it out, you’ll be able to follow the step-by-step tutorial at the end of this post without a problem.

Man looks at road map while woman drinks from water bottle

Can I Use Bleach?

Bleach is an incredibly powerful chemical that makes some beginner RV owners worried about whether or not they can use it. Contrary to popular belief, bleach is often used to sanitize drinking water in all sorts of fresh water systems and backpacking scenarios. As long as you dilute bleach properly, you can use it to sanitize the fresh water system.

Don’t forget when you are getting ready to sanitize your system, sanitize the hose, funnels, and equipment you will be using.

Before you get started, you’ll need to get a whole lot of potable water (using a potable water hose), a one-gallon empty water jug, and a gallon of bleach. Follow these instructions to properly dilute the solution before sanitizing the water tank of your motorhome:

  1. Calculate the size of your RV’s fresh water tank. Most motorhomes will have the capacity listed on the outside of the tank where you fill the water. Others will have it located in an owner’s manual. Worst-case scenario, you can look up the make, model, and year of your RV on Google.
  2. Pour 1/4 of a cup of bleach into the clean one-gallon container, topping it off with water to the brim. This mix is the perfect dilution ratio, as mentioned by RV Trader. You want the bleach to be diluted before putting it into the tank. Shake it thoroughly before pouring it into the system.
  3. Continue step 2 for every 15 gallons of water in the freshwater system. For example, if you have a 45-gallon fresh water tank, you’ll need to make three of these containers and pour them into the tank. Fill the rest of the tank with water. For the rest of the cleaning steps, proceed to the last section of this post.

Never, under any circumstances, should you pour bleach directly into your RV’s fresh water tank. Not only can doing this cause damage to the pipes and the tank, but it won’t mix properly. You’ll end up with concentrated bleach pouring through the sink, shower, and toilet. This concentration can be hazardous to your health.

Bleach Alternatives

If you think that mixing bleach is not something that you want to do, you do have some other options that might work better for you. There are products made specifically for this purpose.

Thetford Fresh Water Tank Sanitizer. It is a two-part treatment; first, you clean the tank with the detergent, rinse, and then use the sanitizer.

Another alternative is Aqua Shock H2O Fresh Water Tank Sanitizer/Disinfectant. This product is a broad spectrum micro biocidal that you can use to sanitize your system and to keep your water bacteria-free and fresh tasting.

To prevent foul odors in between tank cleanings, you can try a treatment or freshener.

Using a treatment is a great way to remove foul odors from the water in your tank. You might not need to clean out the tank completely, but a quick refresher will prevent the taste from going stale. These liquid solutions are ideal for maintaining clean water in between sanitization cycles. The Aqua Water Treatment and Freshener by Starbrite is an excellent choice.

How Often Should You Do It?

Sanitizing your RV’s water tank only once isn’t enough. When the water smells, sits in your tank for long periods, you have filled up at a questionable location or the beginning of the camping season are always good times to consider sanitizing your system. You don’t want to get sick, which is why you need to stay on top of the motorhome’s water system as much as possible.

First, clean the water system right after you buy the RV. It doesn’t matter if the motorhome is brand-new or 30 years old; you need to clean it to remove contaminants and other debris.

New motorhomes have chemical tastes that can leach into the water supply, which makes it taste and smell gross. On the other hand, used RVs probably weren’t cleaned any time recently. It’s best to clean it right when you get it regardless.

You should clean your RV’s fresh water system at the very least once every six months. This amount is enough to prevent it from getting gross; however, as I mentioned above, if you meet one of the other qualifications, do it sooner rather than later.

The more you use the water tank, the less it needs to be cleaned (to an extent). When the water is circulating through the system, it doesn’t have enough time to start building calcium deposits, mold, and mildew. Stagnant water is the worst thing for the water tank or filling up with contaminated water.

If you go camping only a few times a year, you should still clean it out before you head out. Never assume that the water is clean even though you’ve only used it a couple of times.

Failure to sanitize the system as recommended can result in a plethora of unwanted issues. Most people who’ve never cleaned an RV water tank might think that it’s time-consuming. Follow the suggestions in the next section, and you’ll see how easy it can be.

How to Clean Your RV’s Fresh Water System

Now that you’ve seen some different methods, reasons, and suggestions for sanitizing the water system in your RV, it’s time to learn the step-by-step process.

Here’s how you can quickly sanitize your RV’s fresh water system:

  1. Empty the fresh water tank. Turn on all of the sinks, flush the toilet, and use the shower. You can have someone help you to have everything running at once. Once the water is emptied, turn off the sources right away. Running the pump when it is dry can cause damage to it.
  2. Create the perfect cleaning ratio of bleach and water, as mentioned earlier in the post. To summarize, add ¼ cup of bleach in a 1-gallon container and fill the rest of it with water. Pour this solution into the water tank for every 15 gallons of water that the tank holds. Using the example I mentioned above, a 45-gallon tank would call for three applications.
  3. Fill up the remainder of the fresh tank with water after putting all the bleach into it. You’ll notice that the tank might have a bit of a bleach smell from the filling location, but that’s natural. Close the lid. Let it sit at least 5 or 6 hours or even overnight.
  4. Turn on all of the water sources again. You’ll need to run water through every single pipe since they’re all in need of a cleaning. Turn on all sinks, showers, toilets, and outdoor appliances that use water. This process might take around 5 minutes, but it’s the easiest part of all.
  5. Refill the water tank with fresh water from the water hose. Repeat the previous step to drain water through every source, removing the remaining traces of bleach. You’ll need to do this two to three times to completely flush out bleach and debris from the pipes and tank.

Don’t forget to change the water filters when sanitizing the system.

Potable water hookup at campground

One of the most important things you can do to ensure that you have safe drinking water is to fill up at sources that you know have potable water. Just because you see a spigot doesn’t mean the water is fit to drink. Filling at a contaminated source will mean that you definitely will have to sanitize your system sooner than you wanted.

If you still don’t feel comfortable using the water from your fresh water tank for drinking and cooking, you aren’t out of luck.

Another choice for RVers is the Travel Berkey water filter. This filter removes over 200 contaminants and provides a clean and safe option for drinking water and cooking applications. The Travel Berkey water filter holds 1.5 gallons of water; however, they also have other sizes available. The filters remove 99.9999999% of pathogenic bacteria and 99.999% of viruses.

That sounds like the way to go to me to ensure that the water you are drinking while camping is safe. You might like how this filter works so good that you will want to buy another one for your home!


As you can see, sanitizing the fresh water tank of your RV is necessary but very simple. All you need is a few products to get started, and you’ll be guaranteed fresh drinking water wherever you go. Remember to repeat this 5-step process every six months or as needed to keep the tank clean and free of contaminants.

Whether you use diluted bleach or another cleaning liquid, sanitizing the fresh water system of your RV is essential to convenient, healthy, odor-free water while on the road.

Photo of author


Ever since I was little I have been a traveler at heart. It all started when I was six years old and my family took a road trip to Alaska. I enjoy visiting new places and revisiting some of the great locations that I have been to already.