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RV Water Heater Flush and Inspection (Suburban & Atwood)

RV Water Heater Flush and Inspection (Suburban & Atwood)

Should any of us be surprised that conventional wisdom is so often wrong? We’ve all been taught that a flush wand is all we need to clean our RV’s water heater. Water runs clear = clean. NOT! We use a video borescope to take you inside our heater to show the real story.

Step by step, we’ll demonstrate our updated method for effectively cleaning your RV’s water heater.

We’ve been RVing for 1312 years, so you might think we’ve learned everything there is to know about it by now. But as my sensei taught me many years ago, the minute you think you know everything… is the moment you stop learning. We have open minds, and appreciate discovering new things all the time, even about RVing, even after all these years.

We’ve produced three videos about flushing and cleaning RV water heaters. One for Suburban, one for Atwood, and one with an update to the first one, after we discovered that the aftermarket anode we were trying out wasn’t working (see… we’re still learning). This new video replaces all three.

The only real difference between brands when it comes to maintaining them is that Suburban heaters use steel tanks, necessitating the use of a magnesium anode rod. The anode sacrifices itself to protect the tank from corrosion. Atwood heaters have aluminum tanks, obviating the need for an anode. Other than that minor difference, cleaning the tanks is the same.

The vast majority of how-to videos we’ve seen about water heater cleaning use a flush wand, and so do we. But both of our original videos, and this new one, also use white vinegar to chemically clean the tank, where the flush wand only provides some physical action.

Because Atwoods use a plastic drain plug instead of an anode, there’s been no change to our procedure for them. But circling back  to that “always learning” thing, we discovered a flaw in our old procedure for Suburbans. We used to install a new anode rod immediately prior to adding vinegar to the system. We’ve now learned that this was an inappropriate practice, and both modified this new video to reflect the update, and directed our original Suburban video to the new one.

Besides that one change to the Suburban flushing procedure, we decided to challenge conventional wisdom for both brands by picking up an inexpensive USB video borescope to see inside the tank for ourselves. We’d tell you what we found, but that would require a spoiler alert for the video. So you’ll just have to tune in to see what happens!

UPDATE: See the one-year follow-up video here: RV Water Heater Flush & Inspection Surprise!

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Jan Smith

Friday 29th of October 2021

How do I get the vinegar into my water heater if I don't have a "winterizing kit"?


Friday 29th of October 2021

Hi Jan. Without a winterizing kit, it’s definitely more challenging. You could use something like a drill pump (here’s one on Amazon: ) to pump the vinegar in using your city water connection. Or you can remove the overtemp/pressure valve at the top of the water heater and add the vinegar from the top of the water heater. Read through the comments here (and on YouTube) to see what others have tried/suggested.


Tuesday 18th of February 2020

My t&p valve leaks water rapidly when the water heats up. I'm guessing a new tp valve is needed for this to stop? I tried emptying and refilling the to make the air gap but it still leaks when the water heats up? Is there anything I need to know before suggesting i have a bad to valve??


Tuesday 18th of February 2020

Hi Nick. Sorry to hear you're having trouble. We'd try letting some water out of the tank again to try and flush any possible debris that could be stuck in the Temperature & Pressure (T&P) relief valve. If that doesn't work, try making sure it's sealing tightly... let it "snap" back down into place. And even try pushing in on the stem where the flip handle is attached. It may be having trouble seating properly. Then, if those two things don't work, we'd go ahead and replace (and even if they DID work, we'd likely order a replacement to have on hand... because if it's started to leak, even if it goes away, it's likely to come back).

Also... check to see if you're having the trouble regardless of which heating source you use (propane or electric). If it's only happening on one, it's also possible that the thermostat for that heat source is going bad, letting the system heat too high... and thus causing the leaking. If it's happening for both heat sources... then it's more likely that the T&P valve is the trouble.

Hope this helps!

Ken Shumate

Wednesday 30th of January 2019

Absolutely love the video on water tank cleaning. My unit is 7 years old & likely never been cleaned. I plan to use the "fill with 100% vinegar, heat all night" method, but am concerned that it might over-clean, and produce pinholes in the tank or heater tubes. I don't want to wake up the next morning with 6 gallons of vinegar sloshing around inside my RV! Can I run the heater all night with the pressure valve OPEN, and get the same de-scaling results?


Wednesday 30th of January 2019

Hi Ken! Couple of thoughts...

No, leaving the over-pressure valve open shouldn't have any affect on the effectiveness of the treatment... but you might want to rig up something to catch the overflow. As the vinegar reacts with the mineral scale, it's creating a foamy, frothy solution that will bubble out. Aside from being a mess, it could damage any paint it comes in contact with down the side of your RV. So plan to hang a bucket to catch the overflow... or rig up some spout to divert it away from the side, just to be safe. If you're concerned about the potential for the vinegar solution to damage your water heater, you may be better off doing a couple of treatments at lower concentration. It will still remove the scale, but it will be consumed in the process, so that you don't end up with an acidic solution in the water heater for too long. Treat it once at 50% concentration... then repeat. Hope this helps!

roy anderson

Thursday 11th of October 2018

Is it possible to clean or replace the level sensors in a fresh water tank. My level indicators always show 3/4 full, no matter the level. Thanks Roy


Thursday 11th of October 2018

Hi Roy. It depends on what type of sensors your manufacturer used... and what's causing them to no longer report correctly. If the sensors are through-the-wall style, you could, conceivably, clean them. With black/gray tanks, you can add chemicals to the tank and soak the sensors, hopefully removing any "crud" that's causing them to read incorrectly. But in your fresh water tank, you really shouldn't put the chemicals in it that would clean the sensor... so you'd probably have to remove them to clean them.

But if your sensors don't penetrate the wall, and instead read the tank level THROUGH the wall from the outside... there's not much you can do other than replace them.

All that said, we'd recommend looking into installing a SeeLevel system. They have sensors that adhere to the outside of the tank, they report in much smaller increments (giving you a more-accurate reading on the contents), and they have a digital display to show the tank capacity in percentage. You'll need to replace your existing display panel with one of SeeLevel's units (like these available here on Amazon: )... but in most cases, you can utilize the existing wiring that currently connects your sensors to your display. But then you'll probably also need to replace the sensors on the black & gray tanks so that the new panel can display them (it won't work with the existing sensors).

Michael (From South Africa)

Wednesday 22nd of August 2018

Hi guys,

I have another question. Would you not recommend keeping the hot water faucet bypass valves open so that once the hot water geyser is filled up you can turn on the hot water faucet to allow vinegar to flow through and then shut the faucet off to allow vinegar to sit in the plumbing between the geyser and the faucet to dissolve any possible scale build up in there?




Wednesday 22nd of August 2018

Hi again, Michael. Good question. There were two reasons we close the bypass valves when we treat our water heater:

The plumbing lines in our motorhome are made of PEX, which is impervious to just about ANY material building up on it, so we're not worried that there is much, if any, scale buildup throughout the plumbing. We didn't want to have to flush the water system to get rid of the taste/smell of the vinegar (Peter, in particular, really doesn't like the smell).

If you have particularly hard water, or are concerned that you've begun to see reduced water flow as the result of possible mineral buildup, by all means... pump the vinegar solution through the plumbing and allow it to sit. We'd just recommend that you leave at least one faucet open to allow the pressure to release. As the acid reacts with the scale, it releases gas that could cause the pressure in the lines to exceed their capability (we don't have to worry about that with our water heater because it has an overtemperature/overpressure release valve).

If you do plan on doing this, it could be a reason to go with the citric acid powder instead of vinegar, since it would smell/taste as bad if you don't flush it out completely. ?

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