Over time, minerals in campground water can build up in RV water heater tanks, so we need to clean it as part of routine maintenance. I usually do this once a year, typically before the camping season starts, but it’s flexible based on personal preference.
To descale my tanked water heater, I follow these steps: First, I cool and empty the tank, turning off power and letting it cool down. Then I set it to bypass mode and relieve any pressure. Depending on the type of water heater, I either remove the drain cover or anode rod to empty the tank completely and use a water heater flush wand to remove loose buildup.
Next, I connect a threaded adapter and a garden hose with a shut-off valve, and fill the tank with food-grade vinegar or a 50/50 vinegar-water solution. The amount of vinegar depends on the buildup in the tank. After filling, I let the solution sit in the tank for several hours or overnight, optionally turning on the water heater to speed up the process.
Finally, I drain the solution, flush the tank with fresh water, and check for any remaining buildup before reassembling the tank and refilling it. It’s a simple but important maintenance task to keep my water heater functioning well.
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VIDEO TRANSCRIPT
RVing takes us many places and also exposes our hardware to multiple water sources throughout our travels. Over time, dissolved solids in the water can build up in the water heater tank and need to be cleaned and removed as part of your routine RV maintenance. This is a really easy way to descale your tanked water heater and requires minimal tools.
Hey there and welcome to RV Gear and Far. I’m Joshua. So how often should you descale your tanked water heater? It all depends on the makeup of the water you input into the system, but at least once a year is a great rule of thumb. I like to coordinate it with getting my RV ready for the beginning of the camping season, but it’s really personal preference.
Ultimately, once or twice a year, you can’t go wrong. And if you’re watching this but have never descaled your tanked water heater, now’s the best time, regardless of what time of year it is. Thankfully, it’s a simple process. Here are the steps that I take to descale my tanked water heater. As you can see here, this is a quite a bit of sediment and buildup inside of my water heater tank on the lining of the walls, along the electric heating element and chunks of deposits sitting at the bottom of the tank.
That’s what we’re going to try and remove and clean out. Step one is to cool and completely empty your water heater tank. Begin by turning off the power, both electric and propane to the water heater. We’ll then want to cool the tank down, either by letting it sit overnight, or a quicker way is to turn on a hot water faucet and use up the heated water, running it through the faucet until cool water flows out of the hot water side.
At this point, we’ll set the water heater into bypass mode, either at the tank itself or on the water management panel. Once our water heater is cool and set to bypass, I begin by quickly relieving any pressure in the tank with a quick burp of the T and P valve, but leave it closed. That’s temperature and pressure valve at the top.
If you have an Atwood Dometic brand water heater, you’ll remove the drain cover, either a plug or a plastic cap. And if you have a Suburban brand, you’ll remove the anode rod. This can be accomplished with either a socket and ratchet. Or you can pick up one of these handy anode rod tools that simply uses a screwdriver as leverage.
After the drain plug or anode rod is removed, water will start to gurgle out. Now open up that TNB valve at the top, and once you allow air behind water inside the tank, the entire tank will empty out quite rapidly. You could have left that temperature and pressure release valve open when we broke the tank.
It just allows that deluge to flow immediately upon removing the bottom plug, and I found that this sequence gets me a little less wet in the process. Once the tank is emptied, you can grab a water heater flush wand and attempt to flush out as much loose buildup as possible. The wand isn’t crucial for this process, and if you think about it, a small stream of water isn’t necessarily dislodging much on its own, but rather it’s a way to get water into the tank to flush through the drain hole.
Don’t If you’re not going to use a flush wand, I’d suggest opening your bypass valve and allow the city water to flow through from the back of the tank out the now open drain hole. Ultimately our goal here is to get as much of that loose sediment out as possible. That way the chemical reaction with the vinegar during our next step has less material to react with and we’ll finish faster and hopefully more completely.
Next we’ll need a threaded adapter, which may be the only specific item for this process you need to buy, unless you choose to use a flush wand. And a note on that, I personally like to use a flush wand, but I tried this inexpensive plastic wand, and it split the first time I used it. I now use a metal wand, and although expensive, I don’t anticipate any durability issues with it.
Just make sure you’re not scraping the inside of the tank with the wand, but letting the water do the work. I’ll put links to this and all the other products used in this video in the description down below. If you have an Atwood Dometic brand heater, the ones with only a drain plug, you’ll need a half inch NPT to three quarter inch GHT adapter.
NPT stands for National Pipe Thread and GHT stands for Garden Hose Thread. Make sure you get the male or female version of this adapter based on whether your heater uses a plug or a cap to close the drain. And if you have a Suburban brand, the ones with the anode rod, you’ll need a three fourths inch NPT to three fourths inch GHT adapter.
Next, you’ll thread the adapter into the water heater. While I’d recommend using plumage tape on the threads here, as you can see, I forgot. And since this is only a temporary use, it’s no big deal. But please note that this connection should have thread tape installed when we close it up after cleaning.
The other end will connect to a garden hose via a basic garden hose shut off valve. These two connections don’t need plumber’s tape because they’re designed to seal with these rubber washers. Install the adapter, then the shutoff valve, and then your garden hose. A short length of hose is preferred for this, but technically if you wanted to use any of your freshwater hoses, you could do that as well.
It would just take a while to get the vinegar through that long hose and into the tank. At this point, we need to make sure that the water heater is in bypass mode, the TMP valve is open, and our hose is hooked up via the adapter. Our next step will be to fill the water tank with food grade vinegar or 50 50 vinegar water solution.
So how do you know what solution to use? Well, it all boils down to how much buildup you’re trying to dissolve. There will be a chemical reaction between the vinegar and the mineral buildup in the tank. If there are more deposits than the vinegar solution can react to, the vinegar will get used up, yet deposits will still remain.
On the flip side, if there is more vinegar present than build up to react with, then we’re wasting money on unnecessary vinegar. So what’s my recommendation? If you’ve never descaled your tank, then I’d do 100 percent food grade vinegar. If you have a 6 gallon tank, then you’d fill it with just about 6 gallons.
If you have a 10 or 12 gallon tank, then you’ll need that many gallons of vinegar. If you keep up on your annual water heater flushing and maintenance, you’ll probably be able to get away with a 50 50 solution from here on out. But it’ll all depend on the water sources you’re using. With the holes held above the highest point of the water tank and the shut off valve open, pour the vinegar into the tank until the fluid starts draining out of the open TNP valve at the top.
If you’re doing a 50 50 solution, add your vinegar first and then either fill those gallon jugs with water or use the hose to top of the tank. Once the tank is full and liquid is starting to come out of the TNP valve, close the shut off valve and then close the TNP valve. At this point, it’s a waiting game.
The vinegar is doing its job inside the tank and reacting with the mineral buildup. The next step is optional. If you choose, you can now turn on the water heater and speed up the process a bit. Some folks turn the water heater on either propane or electric and let it sit for four to five hours. Others don’t use any heat and let it sit for 10 to 12 hours.
What I’ve had good success with in the past is turning on the water heater for about an hour to bring the solution up to temperature and then shutting it off and leaving it sit overnight. Here’s a smaller example. When I do this process in my water kettle, I add a 50 50 vinegar water solution, heat it up and let it sit for half an hour and then dump the solution.
The kettle is completely free of visual buildup at that point. Now, once we’ve let the appropriate amount of time pass, make sure the power is turned off to the tank and it’s now time to drain the solution. Simply open the shutoff valve, then the TNP valve and drain the solution. If you’d rather not dump vinegar onto the ground, or get your campsite wet, you can drain it into a bucket.
Or you can use this nifty gadget that RV Bucket sent me. It’s a four gallon bucket that hooks up to your sewer hose for easy dumping. Once the solution is drained from the tank, I’ll then remove the hose, shut off valve and adapter, and flush the tank again with fresh water, either using the wand or by opening the bypass valve and letting the city water or my tank and pump flow for several minutes to rinse it out.
Then grab a flashlight and look inside the tank. Is it clean and free of buildup? If not, you may need to repeat the process. Once you’re satisfied, you’ll reinstall your drain plug or anode rod, making sure to use plumber’s tape to seal the threads. Tape should be wrapped in a clockwise direction when looking at the threads, so that as it’s turned into the fitting, the friction of the threads should work to tighten the tape, not unravel it.
And a minimum of three wraps is recommended for a proper seal. If you have one, anode rods are recommended to be replaced annually, or when 75 percent of the material or weight have been lost. Close the temperature and pressure valve and open the bypass valves to refill the tank. At this point, we successfully descaled our tank to water heater, flushed it, and refill it.
We’re now ready to turn on the power to the heating element of choice, and wait for the tank to heat up. Hopefully you found this helpful. If you enjoy RV tips, gear reviews, and how to’s, please consider subscribing to the channel. Happy camping!