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Perhaps your water has started smelling funny or tasting a bit off, or maybe it’s just been a minute since you gave your RV water system any TLC. It could even be that you just pulled your RV out of storage and want to ensure your tank has a fresh start for the camping season. Whatever the reason, it’s never a bad idea to sanitize RV fresh water tank and water lines. In fact, this is something all RV owners should be doing fairly regularly. 

In this article we will discuss why you need to sanitize RV fresh water tank systems, when this should be done, and how to go about it. Let’s get started!

Why Sanitize Your RV Fresh Water Tank?

Your RV fresh water tank gets filled wherever you happen to roam. Sometimes the water used may not be as clean as you’d like. On top of that, when water sits in the tank for a long period of time, bacteria, mold, and mildew can grow in the tank as well as in the water lines. 

By sanitizing your fresh water tank and RV water system, you kill off anything that might be starting to grow in the tank and/or lines. This helps keep your family healthy and happy so you can continue to enjoy your RV travels for years to come. 

Woman washing hands in sink

When to Sanitize RV Fresh Water Tank Systems

Okay, so cleaning your fresh water system is important, but how do you know when it should be done? Generally speaking, it’s best to sanitize your RV fresh water tank every six months or so. That said, if A) you notice that your fresh water has an odd taste or smell, 2) it has been sitting in storage for quite a while, or 3) you have reason to believe that less-than-clean water was used to fill the tank, cleaning it is definitely a good idea. 

What You Need to Sanitize RV Fresh Water Tank and System

Fortunately, cleaning your RV fresh water tank and lines is pretty straightforward, and the supplies are even simpler. All you need to get that system sparkly clean is some regular bleach, a funnel, and a good, clean water source. Run out to the store and grab some bleach and a funnel so we can get started! 

How to Sanitize RV Fresh Water Tank

Now that you know why and when to sanitize your RV fresh water tank and you’ve gathered the supplies to do so, let’s get started on the actual cleaning process. 

Below are the steps you’ll need to follow for a shiny clean tank. 

Turn Off the Water Heater and Pump

Start by turning off both the water heater and the water pump to avoid damaging either one while the fresh water system is empty. 

Bypass the Water Heater and Filter

Bypass the water heater as well as any onboard filtering system you may have. 

Drain the System

Drain the entire fresh water system by removing the water heater plug and opening the low-point drains on your RV. Opening faucets will also help with this process. 

Close Low-Point Drain Valves

Once all water has drained, close the low-point drain valves. 

Create Bleach Mixture and Add to the Tank

To create your tank sanitizing solution, you will need about ¼ cup of bleach for every 15 gallons of water your fresh water tank holds (so about ½ cup for a 30-gallon tank). Calculate how much bleach you need and add that amount to about a gallon of water. Using your funnel, add the mixture to your freshwater tank. 

Fill the Fresh Water Tank

Once the bleach mixture has been added, fill the fresh tank the rest of the way with potable water. 

Turn On the Pump and Open Faucets

Turn your water pump back on and run every faucet in the RV one at a time until you smell bleach, turning each faucet off before you move onto the next. 

Turn Off Pump and Let Sit for 24 Hours

Turn your water pump back off and let the bleach sit in the system overnight. 

Drain the System

Drain the tank and the lines by opening the low-point drains once again. You can also open the faucets (without running the pump) to assist with the draining. 

Close Low-Point Drains and Refill the Tank

Close the drain valves and faucets and refill the tank with potable water. 

Turn on Pump and Open Faucets

Turn on the water pump and open each faucet individually, letting each one run until you no longer smell bleach. In this instance, it’s better to run too long than turn off the flow prematurely. You want to be sure all of the bleach is gone from the tank and lines.

Refill and Flush as Needed

If you go through a whole tank of water and can still smell bleach, refill and drain as needed.

Replace Water Heater Plug and Turn Off Bypass Mode

Finish the job by replacing the water heater plug and switching out of bypass mode. You will also have to add your onboard filtration system back into the mix if you have one. 

Note: Because you’ll be running your faucets throughout this process, you will want to start with an empty gray tank and might even want to have sewer hookups for dumping mid-project. 

Prefer a visual of this process? This video is a good place to get just that.

As you can see, it is fairly easy to sanitize RV fresh water tank systems. Adding this process to your RV maintenance schedule is a great way to ensure your RV plumbing is in tip-top shape while you explore the country!

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