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Can a Water Heater Last More Than 15 Years?

Can A Water Heater Last More Than 15 Years? This One Probably Didn't.

We’ve been trained to believe something that’s just not true.  Go out and ask a hundred people how long a water heater can last, and the majority probably will say it’s in the range of 10 to 15 years.  Where did this idea come from?  Well, it’s nothing more than an assumption based on how often water heaters get replaced.  But what if a water heater could last decades?

As it turns out, water heaters really can last decades?  Larry Weingarten, one of the nicest and most knowledgeable hot water experts in the world, wrote this in his new book*:  “The average life of tank-type water heaters is nine to twelve years, but with periodic maintenance I’ve gotten fifty years from them!”

Wow!  That’s my goal now.  Especially since I spent a bunch of money on a nice heat pump water heater, I want my investment to last as long as possible.  I definitely don’t want to replace it because the tank goes kaput while the heat pump still has life in it.  The only problem for me with making it last fifty years is also making myself last that long.  If I do, I’ll be 109!  But I’m not sure my anode rod will last that long.

Check and change the anode rod

You can go online and find tons of information about how to extend the life of your water heater.  In a quick search, I found articles with 1, 3, 4, 5, 6, 8, 9, and 13 tips for making your water heater last longer.  I’m going to give you just two here.  The first is checking and changing the anode rode.

New vs partially depleted anode rods [Image source: Burton AC Heating Plumbing & More]
New vs partially depleted anode rods [Image source: Burton AC Heating Plumbing & More]
Storage water heaters come with a steel tank lined on the inside with glass.  The water that comes into the tank contains dissolved minerals.  Those minerals can eat away at the glass lining and then the steel tank.  If you do no maintenance, that process will kill the tank in about 9 to 12 years.

But if you put a magnesium or aluminum anode rod in the tank, it attracts the corrosive particles to spare the tank.  That’s why it’s sometimes called a sacrificial anode rod.

The photo above shows a partially depleted anode rod next to a new one.  If you never change the anode rod, all the material you see on that old one will disappear, too.  All that’s left then will be a straight piece of metal not much thicker than a metal coat hanger.  So, check and change the anode rod regularly.

Drain the tank

The second big thing you can do to make your water heater last decades is to drain and refill the tank regularly.  Over time, sediment builds up in the bottom.  Some of it comes in with the supply water.  Some of it is created in the tank.  Where do you think that stuff from the anode rod goes as it corrodes?

Draining a water heater regularly helps keep it free of tank-killing sediment
Draining a water heater regularly helps keep it free of tank-killing sediment

Draining the tank is easy.  All you have to do is hook up a hose to the drain on the bottom and let it drain to the outdoors or to a nearby drain.

Sediment from the first time I drained my water heater tank
Sediment from the first time I drained my water heater tank

I’ve drained mine once and need to do so again this year.  You can see in the photo above that I got a little bit of sediment out of the tank.  That was after two years of use.  Our water supply here in the Atlanta area is pretty good.  It must be because the water heater that I replaced was twenty years old, and I’m sure it had little or no maintenance in its lifetime.

Believing impossible things before breakfast

Do those two things and your water heater can last decades.  The frequency that you’ll have to change the anode rod and flush the tank will depend on the quality of the water you put in the water heater.  If you have hard water, which has a higher mineral content, your anode rod will corrode faster.  Be careful about trying to extend the life with a water softener, though.  See Larry Weingarten’s comment below.

For those of you who haven’t had breakfast yet today, I hope I’ve helped you believe at least one “impossible” thing.  As the White Queen in Lewis Carroll’s Through the Looking Glass said to Alice, “”Why, sometimes I’ve believed as many as six impossible things before breakfast.”  It just takes practice!


Post script.  I highly recommend Larry Weingarten’s new book.*  It’s titled “The Philosopher’s Wrench” and is practical, philosophical, and a bit whimsical. 


Allison A. Bailes III, PhD is a speaker, writer, building science consultant, and the founder of Energy Vanguard in Decatur, Georgia.  He has a doctorate in physics and is the author of a popular book on building science.  He also writes the Energy Vanguard Blog.  For more updates, you can subscribe to our newsletter and follow him on LinkedIn.


* This is an Amazon Associate link. You pay the same price you would pay normally, but Energy Vanguard may make a small commission if you buy after using the link.


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This Post Has 41 Comments

  1. Thanks for the tips. Not sure if this is the proper forum, but, you mentioned a water softener for hard water. Is a descaler also an option? My city doesn’t like salt based systems

  2. The life of a heat pump water heater and heat pumps in general has a big impact on the businesses case. Extend the life, extend the competitiveness with a gas system. We see this with solar panels — 25 – 30 year warranties make them long lived assets. So what can manufacturers do to extent the life of water tanks? What can we do to treat water before it enters the tank to extend its life? What maintenance can we do considering how much money is spent for maintaining combustion appliances which extend their lives — costs that are often under stated when trying to compare the lifecycle costs of heating appliances.

  3. Thank you Allison for once again for helping me with “Believing impossible things before breakfast”, lol!

    1. I have it installed on my water heater for 4 years. My previous water heater last only 3 years. Every time I drained it, water was full of sediments. The day after I’ve got a new one installed, I remove the anode and replaced it by the Corro-Protec system. No issue with it since day 1. Now when I drain the water heater, water is perfectly clear.

  4. My old-style basic gas water heater is 9.5 years old, and I installed it myself (fun!) I’ve been draining 3-4 gallons of water out of it every 6 weeks, after reading that tip numerous times online. Question: this is independent from the anode degradation you mentioned in the article, right? You’ll probably tell me to check the anode. I’ll wait to hear from you on this. Thanks in advance.

    1. BD: Yes, checking and changing the anode rod is separate from draining the tank. If you don’t get much sediment when you drain it, you may not have much corrosion going on. Definitely a good idea to check it, though.

      1. I rarely see any sediment at all come out when I drain it. So it will be interesting to examine the anode rod. I’ll check the link you gave to the good YouTube videos and learn how to do it.

      2. Oops, sorry. You did not link any YouTube videos. I was confusing this article with the one I read just a few minutes prior, where you gave links for learning how to solder copper pipes.

  5. Hi Allison. Thanks for the tips. What if I haven’t drained the tank since it was installed 8 years ago and then go to drain it? Am I risking/causing a steady small leak to develop after draining due to some sediment getting stuck at the shutoff and not letting the shutoff valve close completely? I’ve heard this before and am afraid to start another problem after draining a leak free tank as it is. Thanks.

  6. My water heater is over 40 years old. I’ve never changed the anode. Nor have I ever drained it — not once. We’re on typical New England well water — full of iron and other minerals. Yet it works as well as the day it was installed. How do you explain that?

    The answer is that is that it was made to last. It’s a Vaughn Hydrastone-lined steel tank water heater: made right here in Massachusetts. Hydrastone is a cement lining used in commercial water storage tanks:

    According to Vaughn’s website: “We were the first to introduce our HydraStone lined water heaters in the US and we are proud to say, we continue to have the longest-lasting tanks in the industry.” I can second that.

  7. Another thing that, from experience, is super impactful on the life of the water heater is simply where you live (and thus the water quality, the temperature, and the RH of the outside air.

    As we are about to replace our water heater with a HPWH, you might ask how old our gas one is? It’s… original… and thus a bit over 25 years old. “Oh, you must do regular maintenance” you say. Nope. Zero. No anode replacement, no draining, no flushing, nothing. Neighbors? Same thing. That is likely not because the original water heaters were somehow built awesome; it’s because we simply live in a place where stuff lasts longer.

    Our two 3 ton, 10 SEER AC units (also going in for replacement)? 25 years old. Zero maintenance. Our two gas furnace units? Also the originals. Stuff just… lasts here.

    But all that said, yes of course we are actually going to DO maintenance on our new systems when they go in this fall.

    1. Our 115 gallon Selco Hydrastone started leaking and had it replaced a few keeks ago after 28 years,never replaced the anode or drained it! It’s still in the basement because Selco refused to come get it. I estimate its 450 to 500 lbs and I’m in my 70s and there it sits. I found that Vaghn made this magnificent electric water heater, with the Selco name placed on it. Carefull when it’s time to change it out for another, know that you cannot depend on Selco, the people you pay to rent it, will not come and remove it!

  8. If sediment is an issue, plumb a spin-down sediment filter into the H20 heater inlet. Will be adding one to our existing tankless electric, garage-residing unit sometime this summer. Hard TX water… installed a descaler initially, it does seem to help. (3M variety, SS tee, I believe Aqua-Sense is the brand of replacement cartridges… less $$ than 3M brand)
    Installed a pressure-reducer behind the stacked, front-loading washing machine about six months ago, (the reducer has a sediment screen) astounded to really see how much SAND is in our water.

    Access behind the washing machine is a pain, so will replace the filtering pressure reducer with a non-filter one and add a sediment filter to the water heater instead. This will considerably cut down on the sediment that regularly plugs the washing machine valve screens, necessitating disconnection of the hoses every six months to clean them. (machine takes forever to fill when the screens are clogged.) Both washer hoses connected to the hot spigot with a wye; (cold spigot capped off) everything washed/rinsed with 110-degree water… CLEAN clothes!

    Sediment filter on the H20 heater should also cut down on kitchen faucet aerator cleanings too.

  9. We have a water heater that is 34 years old and no maintenance has been done. It’s a model from Ace Hardware.

  10. Do any manufacturers still make water heater tanks out of Monel Metal (1/3 copper and 2/3 Nickel). Rudd made then back in the 50 and 60s. They lasted forever.

  11. Great tips – I’ve replaced the rod on my father’s water heater (an AO Smith), and all it took was the right socket and a breaker bar. Piece of cake.

    The house we recently bought came with a Bradford-White water heater – their anode rods are integrated into the hot water outlet. Super irritating, but I guess it gets the plumber a service call since I don’t have the skills or tools for cutting / soldering copper. Whenever it kicks the bucket, we’ll be getting something from AO Smith (aka State aka Lochinvar aka some others) or Rheem…

  12. Maybe Ken Z in hia comment has the clue to accomplishing something impossible before breakfast…..the word “impactful”. I wanted to check the anode in ours. First I had to find it. Instructions supplied with the heater are generic to the entire brand and give no clues to the replacement part. There is a cap in the right place but first I had to dig out a bunch of injected foam to find the hex head of the anode. Then I got the correct socket and breaker bar and yanked, then yanked again…no joy. The rod is frozen in place. I was preparing to move the heater to our new basement’s mechanical room so I drained it. That went well and there was little sediment. The heater is 50 gallons and very occasionally we run out of water. We’d just added essentially a whole apartment under our house so I figure I will do something in the nearish future to replace the heater with a bigger and maybe more efficient one. Still, any good tips anyone on getting out a stubborn anode, automotive air-powered impact wrench??

  13. Hi Allison and many thanks for your discussion of my book and also for getting into the many nitty gritties of hot water. There are a few things I’d like to comment on… The two things most important to me in having a quick look at a heater are anode, and temperature and pressure relief valve. These are for longevity and safety. Anode life varies dramatically, from roughly ten years down to six months, depending on the water and quality of the glass lining. In my area, one out of four relief valves does not pass the simple test of operating it, and some are plugged solid, so they serve no purpose at all… You mention magnesium and aluminum anodes. I remove aluminum rods and use only magnesium if there is any chance at all of the water touching someone or being ingested. Aluminum is a known neurotoxin, so in my mind is guilty until proven innocent… About draining the tank of sediment, I like to flush tanks. This involves replacing the drain valve with a full port ball valve and also installing a dip tube (most tanks have dip tubes) that is curved at the lower end. Leaving the water on, this then creates a swirl of water, stirring up sediment and helping it to leave, when the new drain valve is opened… Finally, there is soft water and there is softened water. The first is like rain water. The latter, most of the time replaces the magnesium and calcium hardness with sodium. This actually makes the water more conductive, and can greatly reduce the life of the anode. I see anodes down to a bare wire after six months only in over-softened water. Hope all that helps!

    Yours, Larry

    1. What about Zinc-Aluminum anode rods?
      My hot water develops a rotten egg smell when left untapped for a time… like when we are out-of-town.

      1. Hi, Aluminum-zinc is fine as long as you remember that the water has aluminum in it. The zinc is there to mask the odor. It works in mild cases. Another approach is to use a powered anode. They do not seem to generate hydrogen gas, which the smelly bacteria like, so do a good job nearly all the time, of getting rid of the rotten egg odor. Yet another trick is to put hydrogen peroxide in the tank. This adds oxygen to the water, which the sulfate-reducing bacteria don’t like.

        Yours, Larry

    2. Dear Larry, Thank you for your valuable information. Can you comment on water that is softened with KCL salt instead of NaCL? Does the dissolved KCL conduct as well as the NaCL? How often would you check the anode rod if your water was softened with KCL?
      My water was extremely hard – 17 grains per gallon on a scale where 10 is very hard. Now I have a water softener, using KCL, and water tests as extremely soft. I just tested it at slightly less than 25 ppm.
      Our current water heater is about 20 years old and we are currently discussing with a plumber to replace it very soon.
      Thank you for your advice,

  14. My water heater was installed in 1962! I drain it every 5 years or so, and (sadly) plan on replacing it with a heat pump unit this year.

    1. @Joe Vance
      Just out of curiosity, why would you replace a 62 year old water heater that still works? You are on track to have the oldest water heater in America.


  15. Hi Joe, That’s pretty amazing! What brand is the heater? That was around the end of the time you could still get copper and Monel tanks. Also, what is your water like? Thanks!
    Yours, Larry

  16. @David Fay
    My plumber tells me that it’s a borderline electric hazard! I’m about to do a bathroom remodeling and keen on the lower running costs of a heat pump too. Sadly I’m told not to expect 62 years out of the next one.

    Brand unknown, as it’s covered in a an insulation wrap. Copper construction. And soft water here. It makes some rumbling noise when the element is on, which I’m told is related to sediment, presumably sitting below the drain connection?

    1. Hi., Copper construction explains a lot. There is an old approach to water heating called “tempering tank”. If you keep that copper water heater, but strip off the insulation and put it in a warm place, it can be used to feed your main heater. The warmed water reduces the strain on the main heater. When electric heaters were new, they used to recommend tempering tanks to increase the performance of the electric tank.

      Yours, Larry

  17. A couple of things.
    We have well water with lots of minerals and had a water heater last at least 35 years. In the city where they use surface water heaters only last 10 or 15 years although the Vaughn stone lined ones we installed with solar back in the 80s lasted much longer. This may be due to PH, air, or conditioning that the city does.
    We always replaced the magnesium rods in the solar preheat tanks in well installations because the magnesium reacted with the sulfur freeing bacteria that was often in the water that would make the water smell.
    You didn’t mention the Marathon tanks by Rheem that are made of polybutylene and are guaranteed for life. They don’t have an anode rod as they don’t have any ferrous metal. I wish Marathon made a heat pump water heater.

  18. I forgot to mention that you will find that a lot of water heaters are installed in basements with low ceilings and there may not be clearance above the water heater to get the new one in.(the old one may be reduced to the point you can get it out.)
    The electric anodes are probably the way to go so the above is not a problem. I believe its the same technology that is used on pipelines to reduce corrosion. Back in the 1930s some wind systems were used to provide the power for pipeline corrosion protection.

  19. I have been (happily) using Steibel Eltron 220E HP water heater since 2016. Recently I have installed the water softener system so hopefully it will increase the life of the heater by 4-5 years, fingers crossed!!!

  20. I just replaced my 26 year old Rheem water heater which was working perfectly well and not leaking.
    Although I never replaced the anode rod, I drained it every 6 months and kept temperatures around 115°
    With only my wife and I in the home it really didn’t run that often. I don’t think that this was an exceptional water heater and attribute its longevity to maintenance and moderate temperature setting.

  21. In 2021, I replaced a rheem gas 60 gallon install in 1994, figured it was time. The drain valve was plastic and had a crack, the element had signs of flare up and I wanted to go electric. 27 years is pretty good but didn’t want to risk my new basement suite cabinets for when it did go…. even with the flood stop solonoid, pan and floor drain. Insurance is typically the big reason for replacing as they won’t cover if the tanks are over 10 years old.

  22. One downfall of running a water heater until it dies is that the replacement is often “whatever’s on the truck”, as a replacement is often needed ASAP. Also, if someone wants to install a heat pump water heater, particularly if they’re switching from a gas unit, there’s typically some additional work involved beyond just swapping the tank (dealing w/ condensate drainage, running wiring + circuit install, etc.). So we’ll typically advise clients to be proactive when moving to HPWHs, aiming for replacement once existing equipment gets much beyond 10 years.

  23. I forgot to mention that the 27 year old rheem had minimal maintenance done on it. In the 27 years I flushed the sediment twice and never replaced the anode but I have very soft water so that likely helps to extend the lifespan.

    Prior to swapping out the gas with electric I had the electrican install a breaker and a JB right next to the water heater location so when it came time to swap it to electric, the electrical portion was already done. The plumber did have to cap the gas line and cap the exhaust duct.

  24. Love to see an update for your HPWT energy usage – I’ve installed the open source iotawatt energy monitor and I’ll compare the results once I get a year of data.

    I have the Rheem 80 gallon hpwt and configured it to be heat pump only and have the four schedules with one at 140F to clear any legionaries, the others set at 110 and 120. Thank you for the tips !

  25. US Craftmaster 50 gallon electric, 5.5 kW, with ‘Energy Smart’ control board and lifetime warranty. Installed by us in 2003 and still going strong. I’ve flushed it twice over the years and replaced the failing control board (high pitched noise) myself with free part 3 years ago. Original anode rod. Water here is city treated and medium hardness. We generally keep it at 120F, but I have bumped it up to 140F a few times for sanitation and vacation mode is around 50F. It sits in the basement with a low ceiling, so I checked the anode rod by disconnecting and removing one element when the tank was empty.

  26. Hi J, Looking it up, it seems all US Craftmaster offers is up to a 12 year warranty these days. Might be good to double check your warranty. Anodes can get coated over with hardness from the water and make it look like there is more sacrificial metal left than there really is. I’d replace the anode with a magnesium one sooner than later. The anodes are available as segmented rods, so can fit into tanks with low overhead.

    Yours, Larry

    1. Thanks for the tip about the segmented anode rod. I’ll do a more thorough inspection of the current rod next time I flush the tank.

      It actually is a lifetime warranty. Tank was sold at Lowes and I bought it back in 2003. This lifetime warranty offer went away sometime after that. I’m sure they were losing money on it.

      I’ve read the coating of calcium carbonate inside a water heater tank actually extends the life of the unit by preventing salts in water from contacting imperfections in the steel coating. Any studies verifying this? I would also be interested in knowing if water softening systems hasten the demise of water tanks by salts attacking such tank imperfections and causing corrosion. My neighbor installed a home water softening system and a few years later his tank developed a leak. Coincidence? He replaced it with a 120 amp, whole house, ‘instant’ hot water unit, mostly due to his dissatisfaction with leaking water tanks. Our neighborhood is all electric.

  27. Hi and yes, a film of scale build-up does seem to protect and slow rusting. Often, the action of the anode is what creates that film as it works to protect any bare steel it “sees”. The National Association of Corrosion Engineers (NACE) is where I’d expect to find any literature on it. There is also a book, “Corrosion Engineering” by Fontana and Green, that is a great resource for all things corrosion.

    Salt softening increases the conductivity of the water, making the anode get used up faster…. sometimes much faster. I’ve seen anodes completely consumed in six months in over-softened water. NACE suggests leaving 60 to 120 ppm total dissolved solids in the water and not softening it down to zero, which some people like to do. That might explain your neighbor’s heater problems.

    Yours, Larry

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