RV Water Heater Flush and Inspection (Suburban & Atwood)

TheRVgeeks Annual Maintenance, Maintenance, Plumbing, Water & Sewer 43 Comments

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!

Recent & Related Videos:

Featured & Related Products & Services:

Needed For Both Brands, Suburban & Atwood:

Suburban Water Heater:

Atwood Water Heater:

Just For Fun! wink

We're handy RVers, not professional technicians. We're happy with the techniques and products we use, but be sure to confirm that all methods and materials you use are compatible with your equipment and abilities. Regardless of what we recommend, consult a professional if you're unsure about working on your RV. Any task you perform or product you purchase based on any information we provide is strictly at your own risk.

We sometimes receive products for evaluation at no cost, and The RVgeeks are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites. But our opinions are our own, you won’t pay an extra penny, and we only link to products we personally use, love and can recommend to friends with complete confidence.

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Comments 43

  1. 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??

    1. Post

      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!

  2. 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?

    1. Post

      Hi Ken! Couple of thoughts…

      1. 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.
      2. 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!

      1. Thanks for the quick echo! I’ll try the gradual approach. Also, I attempted to remove the pressure valve & fear breaking the water heater from the force it will take. I bent the handle on the plumber’s wrench & did not succeed yet! So my plan is to suck vinegar into the heater via the “winterizing” hose & hope the cleansing process doesn’t wreck the pressure valve. I may get the borescope to better monitor what’s happening deep inside.

  3. 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

    1. Post

      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: https://amzn.to/2yvtdKD )… 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).

  4. 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?



    1. Post

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

      1. 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.
      2. 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. ?

      1. If only there was a like button here!

        Thanks for the solid feedback guys

        Stay in touch!


  5. Just flushed my hot water heater using the wand method and noticed a lot of scale coming out. Would using a portable water softener, such as the “On the Go”; SIGNIFICANTLY reduce scale build up? Is it worth the expense and effort to buy and use the water softener; or is this annual vinegar tank cleaning process sufficient to keep the water heater from premature failure do to scale build up?

    1. Post

      We’ve gone back and forth on the idea of using a water softener, but have never done it. Seems like too much effort and space taken up for us full-timers with limited room on board. We probably should consider it, but so far, we haven’t bothered. There are benefits… fewer water spots on things, better for your hair and skin, potentially better tasting. Note: for those with high blood pressure (which one of us is on medication for), you have to use a different type of salt to avoid the increased sodium.

      We think that some of the decision depends on where you RV. If you spend lots of time in the Desert SW, we’d definitely be more inclined to do something about the water, since it’s pretty awful. That’s the only place where we RV that we don’t drink the water (luckily, they have purified water machines on just about every corner, and we fill and re-fill 2.5 gallon water containers for drinking purposes).

      We’d suggest getting a baseline of the inside of your water heater by picking up a borescope like the cheap one we used in this video: ( http://amzn.to/2DYvN0Z ). Then you can know that it’s clean, and see how much scale builds up between cleanings. That’s actually what we’re planning for this spring, since it will be one year since the first time we scoped the inside of the tank. We’re interested to see how much scale has built up in that time, and of course we’ll have a video to report our findings. :)

      1. Thanks for the info and advice. I’m going to get the borescope, etc. and take a before look inside the tank. Then I will do the vinegar cleaning procedure and inspect again. I’m going to hold off on the water softener for now and will inspect again in six months to see how much scale has built up.

        1. Post

          Sounds like a good plan, Frank. One other thing that may be a factor in your decision in the long run (which you probably know, but bears repeating): adding the water softener will do more than just help prevent scale buildup in your water heater. It will also: help prevent water spots in your shower; minimize scale buildup on your sink/shower faucets; and it’s better for your RV’s plumbing as well as your hair and skin.

          So if the water where you RV a lot is particularly hard and causes you to have to run a vinegar treatment more often in order to keep up with it… it may not be that much more work/effort to use a water softener, which will give you those additional benefits.

  6. Great tips! Love the advise. My family and I are going to be hitting the road in June. I was wondering your opinion about doing on the road maintenance and repairs to make money while we are on the road. I was an automotive technician for 13 years and have been a boiler technician for the past 5 years. Do you think that this is a feasible idea? Your thoughts or advice would be great appreciated.

    1. Post

      Hi Joshua! Congratulations on your upcoming adventure! We think that is certainly a viable option, since there are so many RVers who need matinenance and repair help from time to time. We’d guess that your primary challenge might be marketing (getting people to know that you’re available out there), and possibly any issue with RV parks allowing work to be done on-site (of course you don’t have to work in the parks, but it’s nice to have that option). We’d suggest that the most useful resource we can recommend is the Make Money & RV Facebook group. They are a wealth of information, all related to working-age RVers, and should be very helpful: https://www.facebook.com/groups/makemoneyrving/ Hope this helps a bit.

  7. I just did this procedure this weekend. I have an Atwood tank. I was concerned that there was some buildup partially blocking my drain plug hole. It was hard as rock. After the cleaning, it broke right up and I could then get the cleaning wand in to flush it. I got lots of gunk out. I am glad it is cleaned out. I was worried about the blockage. I did get the replacement Atwood plugs but they didn’t fit. My original was slightly tapered but the new ones were not. So I put some teflon tape on the old one and re-used it. Thanks for this great tip and all the other ones!

    1. Post
  8. we have a 2003 mountainaire we are just getting ready to go south and went to test the hot water.we have hot water in all sinks but not in the shower . we just de winterized it so did i turn a valve the wrong way ? thank you in advance for your response

    1. Post

      Hi Karen… the fact that you’re getting hot water at ANY outlet in the RV would indicate to us that your winterizing valves are turned correctly. If the winterizing valves were configured incorrectly, you wouldn’t get hot water anywhere. So it sounds like you may be having a failure of the shower control valve itself. Our friends just recently had this problem with the valve in their Moen shower control… they had hot water everywhere but the shower. We helped them replace the valve body (they bought it at Home Depot) and they were back up and running.

      If you have the owner’s manual for your shower control valve (should be in the big black Newmar binder if you still have that), you can get either the make/model of the whole control valve (you can Google for the replacement valve model # using that) or the replacement valve model # itself. If you don’t, try looking on the trim ring for the control in the shower to find the model #… or give Newmar Customer Support a call (800-731-8300), they may be able to help you identify it.

      The replacement valves are quite often available at the big box hardware stores (Lowes/Home Depot/RONA)… but there are so many minor variations and the valve bodies all look alike, so you want to be sure you pick up the correct one.

      Hope this helps.

  9. your information has been invaluable to us. Just bought a 30 foot gas motorhome and when I retire in a couple months the wife and I are planning a trip from the east coast to Abbotsford Canada. We will be moving to Canada very shortly as the wife is Canadian. I understand you guys are now Canadian, can you give us any tips about RVing needs in Canada and maybe how they differ from the US? Excellent videos, you have a great talent for that.

    1. Post

      Congrats on your new rig! So glad to hear we’ve been helpful in your preparations. We did indeed emigrate from the US to Canada about 10 year ago, also originally from the East Coast. The Fraser Valley is beautiful today. ;-) Actually, the only thing that’s different, at least here in BC where we’ve spent more time than in any other Province, won’t be a problem for you. That’s the lack of very many parks with big-rig-friendly sites, and far fewer with 50-amp service. A smaller RV is a breeze up here, and the 13′ difference in size between ours and yours, along with the reduced power needs, will make it a snap for you.

      Other than that, the people are super friendly and welcoming, the weather is beautiful (in the summer anyway, and winters are wet, but not so cold) and it’s a great place overall (in our humble opinions of course). We love being close to the (again IOHO) most fantastic city in North America – Vancouver. We were just there for the day yesterday, and will be back in for a four-day weekend later this month (renting an AirBnB apt, not with the RV).

      Abby is such an easy hop to Van, with or without the RV. And there are two good parks in the area to stay at: Bunaby-Cariboo, which is walking distance to Sky Train, and Capilano RV Park, which is just across the Lions Gate Bridge from Stanley Park. You’ll need to bring a car for that one, and it’s pricey, but it’s as close to downtown as you can get, and we’ve stayed there many times.

      Safe travels as you head out here to our favorite part of the world!

  10. Great update on the flushing video. I wish I had the plastic plug when I flushed my heater. Would have saved a portion of the anode when I used it as the plug. My MH is stored inside an RV barn so I had to use a large container when flushing to keep it off the floor. I used our garden cart which has a plastic tub inside. But it allowed me to see what came out of the tank after flushing and when draining after the process. Quite a concoction of stuff. Wish I had used my video wand to inspect the heating elements like you did. I’ll have to try it next time. Thanks again for the update.

    1. Post
  11. You Gents sure do put out some real good advice on topics that we all need to know. We all can count on you taking the time to explain the topic 100% and with that take us on a step by step do it yourself project.
    This will be added to my info base projects which will for sure keep us up and running with little or no problems.
    Thanks guys …you both are the best!

    < FISH <

    1. Post
  12. As always, great video and explanation! I have a water softener at home and usually fill there before short trips. I flush and drain at the end of each season. Maybe my Atwood is OK, maybe not. I suspect I’ll spring for the borescope, mainly out of curiosity. I can also use it to check my home water heater where I replace the magnesium anode every two years. I’m told softened water accelerates anode deterioration. If I need the vinegar treatment, I’ll need to re-read the winterizing section of the manual, since I have always just blown the lines out with compressed air.

    AS a slight digression, I agree with your “Water runs clear = clean. NOT!” as it applies to black tank flushing as well. I strongly suspect, based on the design, that many of the”devices” sold for this purpose easily produce clear water but but do not really clean the tank. Maybe the borescope has an application there as well, via the toilet. Just a thought.

    Thanks again.

    1. Post

      Thanks Terry! You hit the nail on the head when comparing this to the black tank, both lacking the ability to see inside to know what’s going on. Our best look at the black tank comes from a clear sewer elbow, which is why we strongly recommend that everyone have one. Of course our borescope may be taking its final trip down our toilet. LOL

  13. Thanks again for the update. I’m always learning new things from your website about how to help maintain my new coach. Thank you for taking the time to share this info.

  14. Great info as usual. One thing I might add…it may sound silly, but I have found the need to wear rain boots whenever I service my water heater. My water heater is positioned a little higher than your’s. I can’t drain it without getting my feet wet, LOL!

    1. Post
  15. Thanks for this. I am a little unclear on the use of the winterizing by-pass plumbing to fill the heater tank with the vinegar…I thought the purpose of the by-pass was specifically to exclude the water heater tank. Why did the vinegar go to “the only available void”, ie the water heater; did you make sure the fresh water tank was full first? How exactly did you position the by-pass system valves to ensure the vinegar went directly to the heater tank? I am a “newbie” to the rv/motorhome experience and your videos have been a primary and invaluable learning tool. Thanks so much. Best Regards. Bill

    1. Post

      Hi William. Sorry if we confused things by mentioning the bypass valves in relation to the winterizing kit. They’re kind of unrelated, but here’s the deal.

      First, the amount of water in the fresh tank isn’t important, as it’s not the fullness of that tank that makes the empty water heater “the only available void” for the water to go to. What prevents water from going into the fresh tank is the fact that the tank fill valve is in the off position. If it were set to fill the fresh tank when we turned on the city water, it would indeed flow into there (probably into both the empty water heater AND the open fresh tank fill, since both would now be allowing water to flow into available voids. The trick to that is simple… only have one path for the water to go at a time; in this case keeping the fresh fill off and the water heater line open. By the same token, all faucets should be off, or the vinegar will simply run up through them and down the drain.

      So, to have the water flow to the empty heater requires the heater bypass valves to be in the “regular use” position (in other words, not bypassed), and the water heater to have space in it (which it does of course since we just emptied it), and for the over-pressure relief valve to be open to allow the displaced air to escape as the water fills the heater tank.

      Bypassing the water heater after filling it with vinegar stops any city water from entering the heater, basically isolating that tank. The reason we do that is because if we don’t bypass, and inadvertently turned on any faucet to anything other than cold, we’d be running vinegar out through the faucet. Some seeping of vinegar does occur during the process, which is why we flush all the faucets out at the end. But bypassing the water heater keeps it to a bare minimum, since cold water that would ordinarily be headed into the heater simply takes a “u-turn” prior to entering the heater tank, and heads straight to the faucets when in bypass mode.

      So just to be clear about the settings for getting vinegar into the heater, you have to have the bypass in normal operating position, or no vinegar (or water for that matter) can enter the heater when in bypass mode. We only bypassed AFTER the vinegar was already in the tank.

      Hope this helps a bit!

  16. Boy that sure did show what is going on inside the tank. I will
    Make sure I do that next spring when we get back. What another
    Great video, guys..

    1. Post

      Thanks ladies! We can now reveal that it’s YOUR Atwood tank in the video. Next year we’ll have to break out the borescope to see what’s happening inside your tank, too. Unless you’re afraid of what we’ll find. ;-)

      Looking forward to seeing you next week.

  17. Hi! I have decided to attempt this, since I have never actually “cleaned” it properly!
    I have rinsed it, but that is it.. I now see that I really need to do more. The video is excellent
    and now I think I can tackle it myself.
    Here is my question: I see that the next morning you fire the HWH up and then drain. Is
    there an advantage to draining it while the water is hot? Or do you think that it will be
    the same success level as waiting on it to cool off first?
    I will do it hot if it will work better, but am thinking that cooler is safer!

    1. Post

      Hi Ann! There are three main factors at work: 1) The vinegar concentration (ratio of vinegar to water). We’d suggest at least about a 50/50 mix; 2) The length of time the solution is in contact with the limescale. We did the 16 hours to get the result we did, but as mentioned, results vary based on how bad the tank was and what the water quality is where you travel; and 3) The heat being on.

      You can absolutely let the water cool before draining, as long as you leave the heat on long enough before turning it off to allow the vinegar to work. If you haven’t cleaned it before, or in a long time, we’d suggest trying this: flush the heater out one morning, and leave the vinegar in the tank all day and night with the heat on the whole time. The next morning, turn off the heater. Then that afternoon or evening, after the water has had all day to cool, drain it and finish the job. It will probably still be warm, but not hot.

      After seeing the results of 16 hours of hot 50/50 vinegar mix, we’re going to do it that way ourselves next year, probably even increasing the mixture to at least 75% vinegar. We’ll of course report back with a follow-up video. ;-)

  18. Pingback: RV Suburban Water Heater Anode Rod FAIL - TheRVgeeks

  19. Wow. Awesome video again guys. Never even thought to inspect and clean the water heater and my wife and I have been RVing for 5years now. We are typical snowbirds so we really on use the RV in the winter. The funny thing is I just recently bought that same bore scope to inspect my wife’s cars heater vents as we have had some unwanted guests living in them during the winter. I will be using the bore scope to inspect the water heater.

    Question: When we return in the spring every year we drain the hot water heater until we get ready to head south for the winter. Do you think that would cause more or less scale build up? And we have a Teflon plug with no anode.

    Thanks again for a great video!

    P.S. Did you see any videos on the new DJI Mavic? If I upgrade that might be it.

    1. Post

      Thanks Randy! Water heater cleaning is an important annual task. Sounds like you’re about to have a new place to play with that borescope! LOL We’re looking for all sorts of places to use it.

      It is generally recommended that you leave your water heater empty when storing for a long period. That will definitely reduce the scale build-up, too.

      Read about the Mavic, but haven’t seen it yet. We got all excited the other day when GoPro announced the Karma. If the DJI looks anything like that, there’s going to be some stiff competition out there! We love our 3DR Solo, but technology marches on, so who knows?

  20. Wow! The difference between the first flush and then after using the hot-vinegar-overnight-treatment is quite impressive.

    Do you find that, depending where you filled the water tank, some years have more scale than others?

    ( When I come south this winter I’m wondering if I should fill up with local mountain-fresh BC water before I leave.)

    1. Post

      Hey John! This is the first year we’ve had a borescope, so we honestly don’t know. But amazing BC water surely contains a lot fewer minerals than that awful stuff in the Desert SW. About the only thing we DON’T love about snowbirding is the water. We drink the water just about all over North America, but not when we’re in the Arizona desert. We fill up before we head South, but doubt we could be miserly enough with water to make it last all winter. I’ll be that King Aire of yours has massive tanks tanks that could handle the job though. ;-)

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