One of the most important maintenance tasks you can perform on your RV is sanitizing the fresh water tank. By keeping things clean, you can be sure that you will always have fresh, safe water to use while you’re camping.
Regularly maintaining your RV fresh water tank might seem daunting at first, but once you do it a time or two, you’ll quickly find that it’s not complicated at all.
Besides, the last thing you want is cloudy, stinking water that is unfit to use while you’re spending time at the campground.
If you’re unsure of how to clean and sanitize your RV fresh water tank, don’t worry. We have you covered.
In this article, we break down the process and explain everything you need to know.
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Why You Need To Clean And Sanitize RV Fresh Water Tanks
Even if you completely drain your fresh water tank, a small amount of water will remain in the tank. Once that water becomes stagnant, it makes your plumbing system a breeding ground for mold, mildew, and bacteria.

That’s why it is extremely important to sanitize your RVs water system regularly. If you or your family ingest or come into contact with the bacteria left behind, it can have negative effects to your health.
How Often Should You Sanitize RV Fresh Water Tanks?
The general rule of thumb is you should be sanitizing your fresh water tank at least once every 6 months. However, if you begin to notice that your water tastes or smells odd before then, you should sanitize your tank immediately.
Some RV owners will perform this task whenever their rig has sat unused for more than two weeks, or every Spring when they de-winterize their water systems.
By adding this task to your regular maintenance schedule, it will guarantee you will have safe, clean water for showering, brushing teeth, and of course, drinking.

What You Need To Sanitize Your RV Fresh Water Tank
Now that you know how important it is to maintain a clean water tank and how often it should be sanitized, let’s look at what materials are needed to perform the task.
The items and materials you will need to sanitize your fresh water tank are fairly common and shouldn’t be hard to find:
- 1-Gallon Pitcher Or Clean Milk Jug
- Funnel
- Bleach
- Measuring Cup
- Clean Water Hose
NOTE: Don’t use a scented bleach or one that has any special ingredients.
How To Sanitize Your RV Fresh Water Tank
Before you begin the process of cleaning your water tank, be sure you have around 12 hours to spare. It’s best to start sanitizing your water tank early in the morning so you have enough time for the sanitization process.
Below is a basic step-by-step process for cleaning your water tank. Consult your RV owner’s manual for specific steps for your rig.
1. Turn Off And Bypass The Water Heater
The first step in the fresh water tank sanitizing process is to make sure your RV water heater is turned off and bypassed.
Leaving your water heater on during the draining process can burn up the heating element in the unit.
The exact process or bypassing the water heater will vary depending on make and model. Basically all you are going to do is close the valves that supply water to, and carry water from, the tank.
2. Drain The Water System
Start by making sure your water heater and water pump are shut off prior to draining the water lines. Open the drain valves under your RV to drain the water lines and the fresh water tank. You will also want to drain your water heater.
3. Mix The Sanitizing Solution
The industry standard and most recommended sanitizing solution is bleach. However, if using bleach concerns you, you can buy a premixed sanitizing solution or you can use white vinegar heated to around 130° F.
When using a premixed sanitizing solution, follow the manufacturers instructions. If you are using the vinegar method, dilute 2 quarts in a gallon of water and add that mixture for every 15 gallons of water tank capacity.
When using bleach, you will need ¼ cup of bleach for every 16-gallons of capacity in your fresh water tank. Check your owner’s manual if you’re not sure how much water your tank holds.

Don’t pour un-diluted bleach directly into your water tank. It can damage the seals, gaskets, and fitting in your plumbing system. Always dilute the bleach in a gallon pitcher or something like a clean milk jug before pouring in into the tank.
Before pouring in the diluted bleach solution and filling your water tank, make sure your drain valves are closed.
If your rig has a hose inlet supply for the fresh water tank, you can pour the solution into the end of the hose before connecting it to your RV.
4. Fill The Water Lines
Now that you have your fresh water tank full of water and the diluted bleach solution, turn on the water pump and open the faucets throughout your RV. Once you begin to smell bleach, turn them off.
5. Let Mixture Sit For Several Hours
Now that the fresh water tank and all water lines have the bleach solution in them, it’s time to wait. You should let the mixture sit for 8-12 hours. This will give the solution the time it needs to kill off any bacteria that might be growing in your water system.
Some RVers recommend driving your RV around for a few minutes to let the solution slosh around in the water tank. What this does is allows the sanitizing solution to cover all areas of the fresh water tank.
If your patience is as short as mine, it’s best to find something else to do while you wait. Now you can see why it’s recommended to start the process early in the morning.
6. Drain The Fresh Water Tank And Flush With Clean Water
After the solution has had time to do it’s thing, it’s time to drain and flush the system. Find a place that is away from plants and anything else that might be harmed by the bleach. You can also use a 5-gallon bucket to catch the water that drains from the lines and tank and transfer it to a place that is safe to dispose of it.
Once the system has drained, close the drain valves and fill RV fresh water tank with clean water. Turn the pump on and open all of the faucets.

Continue this process until you no longer smell bleach coming out of the water lines. When you no longer smell the solution, take a sip of water, if it tastes like the bleach or sanitizer, repeat the rinse process again.
7. Turn Water Heater Back On
The final step in sanitizing your RV fresh water tank is to make sure your water heater is realigned. Open the bypass valves to fill the water heater with water and turn it back on.
Your RV fresh water tank and water lines have been sanitized and cleaned and are ready to be used again.
Final Thoughts
Sanitizing your RV fresh water tank is a vital part of RVing. Don’t always count on an RV park or campground to provide safe, clean water.
It might seem like a hassle to keep your water system clean, but it is well worth it to provide your family with safe water for showering, brushing teeth, and even drinking.
David is a U.S. Air Force veteran who currently lives on the Texas Gulf Coast with his wonderful wife of 26 years and their two furry companions, Gus and LuLu.
As an outdoor and RV enthusiast, David loves to spend his free time taking road trips and spending as much time as possible at the campground with the family in their 2018 Dutchmen Kodiak 201QB travel trailer