Making sure to sanitize your RV water tank is one of the most crucial items of any regular RV maintenance routine. A clean RV water tank will make your travel so much better. You’ll always have clean, fresh-tasting water for drinking, cooking, and even bathing and doing dishes.
Unfortunately, many RVers don’t get around to cleaning their tanks until their water starts tasting strange or comes out cloudy. At this point, cleaning it becomes more of an emergency than a regular maintenance item.
If you’re not familiar with how to sanitize your RV water tank or if it seems too complicated, read on. We break down the process in simple steps and explain how easy it is. Here we go!
Do You Need to Clean and Disinfect RV Fresh Water Tanks?
RV freshwater tanks occasionally need to be cleaned and disinfected. After filling from various water sources during your travels and letting tanks sit for storage, freshwater tanks can grow and house bacteria, mold, mildew, and potentially other pathogens. And while many municipal water supplies will have chlorine in them that helps, thorough cleaning at the beginning and end of the camping season is always a good idea.
Even if you have a thorough RV water filtration system, you’ll want to perform a periodic sanitization of your RV water tank and lines. This way, you know the water coming out of your faucets and showers will be safe.
Items Needed to Sanitize Your RV Water Tank
The good news is you don’t need any specialty items to sanitize your RV fresh water tank. All you need is a large pitcher, a measuring cup, and a gallon of plain liquid bleach. Don’t use bleach with any added fragrances or any other special ingredients.
You could use a special detergent or formula specifically made for sanitizing your fresh water tank, but it’s really not necessary. These simple ingredients are all it takes.
How Often Should You Sanitize RV Water Tanks?
Most experts recommend you sanitize your RV water tanks at least twice a year. Of course, if your freshwater smells or tastes strange, you’ll want to sanitize it right away.
If you’re taking your RV out of storage after an extended period, it’s a good idea to sanitize your water tank then too. You never know what kinds of bacteria might grow while your RV is closed up.
How to Calculate Amount of Bleach Needed for Your Water Tank
There are different levels of bleach dilution for different levels of sanitization. The bleach ratio you put in your tank should be for sanitizing water tanks, not for creating a cleaning solution for surfaces.
For this application, you will need about 1 ounce of bleach per 8 gallons of water in your fresh water tank. Or ¼ cup of bleach for every 16 gallons of water. To determine how many ounces of bleach you need, divide your total tank capacity by eight. If your tank holds 40 gallons of water, you’ll need 5 ounces of bleach (40 ÷ 8 = 5), which is just over 1/2 cup.
Use the calculation we provided above to determine how much bleach you’ll need to sanitize your fresh water system based on its capacity. Then, add that bleach in a diluted solution to your full fresh water tank per the instructions below.
NOTE: Whatever the final amount of bleach, dilute it in at least 1 gallon of water before adding it to the water in your fresh water tank.
Pro Tip: Never Add Undiluted Bleach to Your RV Plumbing System
Never add undiluted bleach directly to your water tank or RV water system. It can damage seals, gaskets, and fittings in the plumbing.
➡ Understanding the different components of your RV water system is key to proper maintenance. Learn more here: How Does an RV Water System Work?
7 Easy Steps to Sanitize Your RV Water Tank
We’ve warned you about using the proper amount of bleach AND diluting it before putting it in your RV’s fresh water tank. So now, let’s go over the seven simple steps to sanitize your RV water tank.
1. Turn Off Water Heater and Drain All Fresh Water
You never want your water heater to be running when you sanitize your RV water tank. Turn it off and drain it first. Leaving the water heater on while cleaning your tank will damage it.
Also, let the water cool and leave the water pump on before draining the heater. This will help to get all the water out.
2. Bypass Your RV Water Heater and Onboard Water Filters
Bypass your RV’s water heater by closing the valves that allow water to flow into and out of the water heater. Yes, it’s that simple.
If you have an icemaker, shut that off and close the valve to it.
If you have an onboard water filter, bypass it as well. This probably won’t be as simple as closing valves, as there’s typically plumbing beyond the water filter that you’ll want to sanitize. If your rig doesn’t have a bypass built-in, remove the water filter and attach a piece of flexible tubing between the connectors.
3. Add Diluted Bleach Mixture to RV Fresh Water Tank
Fill your fresh water tank to between a third and a half of its capacity with water. For example, you should use 20 to 25 gallons of water for a 50-gallon tank. After adding the water, pour in the diluted bleach mixture per the calculation we provided earlier.
Pro Tip: For hopeful #VanLife explorers, you’ll want to know Do Campervans Have Water Tanks?
4. Fill Fresh Water Tank with Fresh Water
After putting water in the tank and adding the diluted bleach mixture, fill your fresh water tank to capacity. It should be completely full so that the sanitizing solution can reach all the nooks and crannies in your fresh water system.
5. Open Every Faucet One at a Time and Run It Until You Smell Bleach
In addition to sanitizing your RV water tank, you’ll want to sanitize your RV water lines, too. So, once the tank is full, open all the faucets in your rig one at a time until you smell bleach. This is how you know that the sanitizing solution has made its way through all the pipes to the various fresh-water fixtures.
Because these fumes can smell quite powerful, we recommend opening some windows and turning on your vents before you turn on your faucets.
6. Let Sanitizing Mixture Sit for Several Hours
Bleach is a powerful sanitizing agent, but it can also cause damage when you use it at full strength. That’s why we dilute it first.
But diluting it also slows its effect on bacteria in the system. Once the solution spreads throughout your fresh water system, let it sit for several hours, so the bleach can do its magic. We recommend upwards at least 5 hours, but upwards of 12 to get everything sanitized properly. Because of this, it is best to sanitize between camping trips or when you know you’ll be away from the RV for most of the day.
If possible, plan it for a day that you have a long drive. Driving around for a couple of miles can slosh the sanitizing mixture around to help ensure that as much of the fresh water system as possible gets treatment.
7. Drain Your Fresh Water Tank and Flush the System with Fresh Water
After letting the sanitizing mixture sit for six to eight hours, completely drain the fresh water tank from your low-point drain. The low-point drain is typically near one end of the fresh water tank.
Once the tank is empty, refill it with fresh water. Run your faucets one at a time until you no longer smell bleach. If you drain the tank but still smell bleach, repeat the process until the bleach smell disappears.
Then, refill the fresh water tank and return your water heater, ice maker, water filter, and other appliances to normal operation.
How Do I Sanitize My RV Water Tank Without Bleach?
Some RVers do not want to use bleach for sanitizing their fresh water tanks to avoid having to handle it. Instead, they will use either baking soda or vinegar solutions in place of the bleach. However, baking soda does not appear to be effective in studies and vinegar is far less effective. We don’t recommend using vinegar for tank sanitization unless it is your only option.
Vinegar is not listed with the EPA as an effective household disinfectant. Its acidity helps with breaking down some scum, but it does not have the potency to actually kill all the germs that may be living in your fresh water tank. Plus, if you don’t get it all out of your tanks and pipes, your camper may smell a bit like a pickle factory.
Bleach is the cheapest, easiest, and most effective way to sanitize your RV tanks. Chlorine reacts quickly and becomes inactive quickly after it does its job. The amount needed is very small and leaves no residue when diluted properly.
Regular Sanitization Keeps Drinking Water Safe and Clean
Now you know how easy it is to sanitize your RV water tank. It probably seems like a lot at first, but after doing it a time or two, you’ll see it’s relatively simple. And it’s well worth the effort.
Not only does it make your fresh water safe for drinking, it also keeps it tasting fresh. Clean, safe water is better for cooking, doing dishes, and showering, too.
➡ Still not convinced your fresh water is safe? Here’s everything you need to know: Is It Dangerous to Drink from Your RV Fresh Water Tank?
Additionally, sanitization goes a long way towards being more environmentally friendly. When you can drink from your fresh water tank, there’s less need to purchase bottled water, which creates a lot of excess trash. Avoiding bottled water can also save you quite a bit of money.
Make cleaning your RV water tank a regular part of your routine – at least twice a year – and you’ll reap the rewards in your health and comfort.
Your black tank requires regular cleaning too. However, you don’t want to use bleach for this task. Read What RV Toilet Chemicals Should You Use? to learn more.
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