RV owners should periodically clean and sanitize your RV fresh water tank. If you don’t, there’s chance that you and your family will get sick from mold and bacteria growing inside the tank. We’ll show you the correct and safe water tank cleaning process to ensure your RV’s potable water is safe.
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We’ve asked our friend Jim Tome of Kleen Tank for his professional advice by writing this guest blog. He’s instrumental on setting the record straight on black tank cleaning and flushing and general RV tank maintenance.
How to Clean and Sanitize your RV Fresh Water Tank
What’s growing inside your RV’s water tank?
Quite simply, it’s mold.
The inside of your RV’s water tank presents the perfect environment for mold and odor-producing bacteria to grow; especially during warmer temperatures.
If your fresh water tank is already dirty from not maintaining it’s sterility, that’s likely contributing to the problem.
How often must you clean your fresh water tank?
If you use your fresh water holding tank at all, you need to sanitize it at least twice a year, no matter how often you use your RV.
It’s recommended to clean it right after you de-winterize your RV, and another halfway through your RVing season.
But, if you’re a full-time RVer or use your RV fresh water holding tank frequently, sanitize it at least three to four times a year.
Before we get into the actual water sanitization process, we’ve got to talk about preparations and precautions.
Fresh water tank cleaning and sanitizing preparation
Prior to cleaning and sanitizing your RV’s water tank, we highly recommend parking your motorhome or towable RV at a full-hookup campsite. You’re going to be flushing your water system. Which in turn, will fill your RV gray tank. So, make certain your gray tank valve is open during this process.
Also, we recommend you wear clothes you don’t care about. We also leave it to the user’s discretion to wear rubber gloves to protect your skin. And, put on safety glasses to protect your eyes from splashes.
Splash-less bleach is a little thicker than regular, household bleach. The active ingredient, sodium hypochlorite, only has a 1-5% concentration. As the label on the bottle will warn, it’s not enough to sanitize and disinfect.
We highly recommend using regular, household bleach instead. Household bleach, as we already mentioned, can be extremely corrosive. So, it’s important to wipe down any surfaces that it may have spilled on with clean water or ethanol.
You’ll definitely want to avoid letting bleach stay in contact with delicate metal instruments or structures (such as your holding tank’s sensor probes) for very long.
Also, bleach can damage or degrade rubber or plastic parts and surfaces, such as water supply and waste disposal plumbing pipes, holding tank seals, and other soft, delicate parts in your RV.
This is precisely why rinsing and disposing of the diluted bleach-water solution used to sanitize your RV’s fresh water holding tanks is so critical.
Lastly, household bleach degrades quickly; especially when exposed to sunlight. Always store bleach in a cool, dry environment in thick, opaque plastic (like the container it comes in!) or glass bottle.
And NEVER mix bleach with any ammonia-based cleaners. Doing so will create toxic chloramine gases and an explosive called nitrogen trichloride.
So, now that we got that out of the way, let’s get down to the nitty gritty of cleaning and sanitizing your fresh water tank.
How to clean and sanitize your RV water tank
The cleaning and sanitizing process is quite simple. You are basically going to get a diluted mixture of household bleach into your fresh water holding tank.
Then you’re going to pump it throughout your RV’s water system. You’ll need to allow it to sit for a couple hours. And then allow it to drain into your gray tank and through your RV’s sewer hose into your campsite’s sewer hole.
The active sanitation and disinfectant ingredient in bleach is sodium hypochlorite. It’s been used for centuries as a disinfectant and bleaching agent. Common household bleach is a very diluted solution of sodium hypochlorite. Really, it’s mostly water but with traces of the chemical.
While not toxic, it can be highly corrosive. It can completely eat through stainless steel if left too long. But, it’s perfect for destroying bacteria, molds and mildews, and most viruses.
To sanitize your RV’s water system, use a quarter cup (two ounces) of household bleach for every fifteen (15) gallons of water that your fresh water tank holds.
Some instructions will say to mix the bleach in a bucket or other container with fresh potable water and then pour that mixture into your fresh water holding tank.
However, that will just make a big mess that can result in bleach coming in contact with your clothes, hands, the side of the RV, and even on the ground.
But there’s a better way.
Instead, using your potable water hose, pour the appropriate amount of bleach (quarter cup or four ounces) for every fifteen (15) gallons of capacity in your fresh water holding tank into an empty water hose. Then, connect the water hose to your RV’s fresh water tank inlet. Finally, fill the fresh water holding tank with potable water (which will also now have bleach in it).
We recommend NOT using a regular garden hose. Only use the special white or blue water hose intended specifically water transfer from the spigot at your site to your RV.
Once full, briefly turn on every water faucet in your RV. This includes the shower head and even flush the toilet until you detect a strong and distinct bleach smell from each water source.
This ensures that the pipes and other fixtures have bleach in them. Your entire RV fresh water system needs to have this mild bleach-water solution in contact with it.
We recommend that you let your RV’s water system and fresh water tank (now nearly full of bleach-y water) set for a minimum of four hours. Or, you can leave it set overnight.
Once the time has passed, pump out the water from your RV’s fresh water tank through the waste disposal system (from each water tap, the shower head, toilet, etc.) into the black and gray tanks. Then, open your sewer valve to allow the solution to go through your sewer hose into the campsite sewer.
We recommend that you fill each of your holding tanks again with fresh, clean water. Then, empty it again to remove any remaining bleach solution.
Once your RV’s fresh water tank is completely empty, refill it with clean, potable water only. Let it sit for an hour. Then pump it all through the system again and empty your RV’s holding tanks one last time. Your RV’s water system and fresh water tank is now sanitized.
Now, wasn’t that easy?!
So, that’s a wrap! Now, you know how to properly clean and sanitize your RV’s water tank and system. We hope this self-help tutorial has helped you understand the process of cleaning and sanitizing your RV’s fresh water tank and fresh water system.
About our Guest Author
Jim Tome, owner of Kleen Tank, an Authorized All Pro Water Flow dealer, has been an RVer for over 15 years. His company provides RV holding tank cleaning services throughout the U.S., but mostly in the Midwest. He posts weekly articles on RVing, tips and advice, and relevant topic on the blog at KleenTank.com. He attends RV rallies throughout the year, giving seminars, answering questions, and teaching RVers about their RV’s holding tanks and waste handling systems.
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