# When to replace a hot water heater? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [June 5, 2016, 2:07am UTC](https://boards.straightdope.com/t/when-to-replace-a-hot-water-heater/756541 "2016-06-05T02:07:26Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![DorkVader](https://avatars.discourse-cdn.com/v4/letter/d/73ab20/32.png) [@DorkVader](https://boards.straightdope.com/u/DorkVader)\ **Post date:** [June 6, 2016, 1:00am UTC](https://boards.straightdope.com/t/when-to-replace-a-hot-water-heater/756541/21 "2016-06-06T01:00:40Z")
water heaters are “only good for” a decade? Huh, I always thought they were one of those “20 year durable goods” items. I did not know! I replaced my 25 year old water heater this spring because the siphon tube disintegrated and clogged up my bathroom faucets (necessitating a new shower valve as well) as well as making me replace the aerator in the kitchen and clean the screen on the washing machine (fuck that pos “dishwasher” my wife swears by) ---
**Author:** ![Mama\_Zappa](https://avatars.discourse-cdn.com/v4/letter/m/71e660/32.png) [@Mama\_Zappa](https://boards.straightdope.com/u/Mama_Zappa)\ **Post date:** [June 6, 2016, 1:29am UTC](https://boards.straightdope.com/t/when-to-replace-a-hot-water-heater/756541/22 "2016-06-06T01:29:15Z")
> [@excavating\_for\_a\_mind](#): > > Another weighing in for “wait until it fails”. > > They typical failure mode for a water heater is for the tank to leak. The tanks leak because of corrosion. Because of this, the tanks are glass-lined. The problem is that, while pure water is neutral, it absorbs CO2 from the air, which makes it acidic. Fortunately, the earth is has a lot of calcium in it, which forms calcium carbonate (a base) that buffers the acidic nature of the CO2. Unfortunately, heating water decreases the amount of CO2 it will hold, which will cause the Calcium to precipitate as lime (which is basic). While basic conditions are good for slowing corrosion in iron, they can attack glass. So (getting around tuit), the tanks can’t last forever. It can be difficult to predict the life of the tanks, however, since you have to know how much calcium is in your water (how hard it is), and the CO2 content when cold, as well as how much CO2 is lost when it is heated (which depends on exact water chemistry). > > So…, just wait until it leaks and replace it. You can do it early, but you might be throwing away a perfectly good water heater for no good reason. Make sure it’s set up in a way that leaking won’t damage the rest of the house, however!! About 2-3 years back, the furnace repair guy came over for the annual inspection. About 2 minutes later he came back upstairs and said “you have a problem”. The heater was leaking - and had been leaking long enough that water seeped out of the furnace room and soaked the carpet just outside (otherwise I might have suspect he’d damaged it himself just to sell us a new heater). It had NOT been doing that 24 hours before, as we’d been downstairs and the carpet was NOT wet. The replacement heater has a pan underneath that has a pipe to the floor drain, so even if it DOES spring a leak it won’t do any damage. Neighbors of ours were out of town when their heater died. I don’t have all the details, I’m sure, but it was leaking constantly (and trying to refill, so the leak continued); some of the water was getting sucked up into their HVAC system somehow and caused damage in numerous rooms of the house. Evidently it was a mess and a half. ---
**Author:** ![MikeG](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mikeg/32/4329_2.png) [@MikeG](https://boards.straightdope.com/u/MikeG)\ **Post date:** [June 6, 2016, 3:16am UTC](https://boards.straightdope.com/t/when-to-replace-a-hot-water-heater/756541/23 "2016-06-06T03:16:14Z")
I like to replace these types of things on my schedule, not theirs. I strongly recommend Bradford White water heaters. I’ve sold American, State, Rheem, Bradford White, GE, and a few others as well. The B-W have by far the lowest failure rate. In addition, you can get a descaling filter that you install on the incoming water line that will help reduce the buildup in the tank that is the primary cause of failure. There are also valves that will sense when the water heater springs a leak and will cut the water and gas supply. Check carefully if you do get one, as a lot of water heaters are not compatible with them. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [June 6, 2016, 1:34pm UTC](https://boards.straightdope.com/t/when-to-replace-a-hot-water-heater/756541/24 "2016-06-06T13:34:47Z")
I’ve occasion to work on water pipes, and as you can guess I usually turn off the water main valve before I start. Also I cut the electric power to the WH, just as a safety precaution (if the water should drain out, the elements will self-destruct). It takes a few days to complete the prerequisite 27 trips to the hardware store for such a task and by then the water in the tank has cooled to room temperature. When done is done (and 5 more hardware store runs), and the water is back on and all the lines purged of air … and the electricity is back on the WH … well, just seems often enough shortly afterward the tank starts leaking. Coincidence, conformation bias, too many episodes of _Mythbusters_, or is the heating water expanding enough to split a seam on an old tank? ---
**Author:** ![FluffyBob](https://avatars.discourse-cdn.com/v4/letter/f/ecb155/32.png) [@FluffyBob](https://boards.straightdope.com/u/FluffyBob)\ **Post date:** [June 7, 2016, 3:09pm UTC](https://boards.straightdope.com/t/when-to-replace-a-hot-water-heater/756541/25 "2016-06-07T15:09:31Z")
> [@aceplace57](#): > > I’d wait until it leaks. Keep an eye on it. Dont let it leak very long. > > Replace with a modern tankless water heater. Prices are steadily dropping every year. I hope to buy one in a couple years. They’ll always cost more than the old tank type. But the long term energy savings makes it worth it. I offer caution on this upgrade now. We were putting these in all the homes we were building a few years ago. We had warranty issues with several of them, new and after a year two. Tankless water heaters are way more efficient, much smaller, have cool features like built in recirculation pumps, but they are much more complicated than a tank. They have a circuit board that is a failure point, heat exchangers that can fail, and are very sensitive to poor venting conditions. The vertical “T” style of vent is standard now and supposedly more reliable but they all can clog up in cold weather. Perhaps it has changed now but after installing probably twenty we found out they should get a yearly acid wash to clean the heat exchanger, which was a service that was hard to even find. More than a few builders I know just will not bother with them anymore. I do mostly Insurance restoration now rather than building infills. The number of claims I have seen from failed hot water tanks are pretty few. Dishwashers and fridges are much, much more common leak risks. Water tanks are usually close to a floor drain and the leak usually starts slowly. Code here requires a floor drain with an open drop (no p-trap) to the main floor drain now for upper floor laundry rooms, they should be required for kitchens also, would save people a lot of grief. Not that I do not appreciate the work. ---
**Author:** ![Kimballkid](https://avatars.discourse-cdn.com/v4/letter/k/b5a626/32.png) [@Kimballkid](https://boards.straightdope.com/u/Kimballkid)\ **Post date:** [June 7, 2016, 4:26pm UTC](https://boards.straightdope.com/t/when-to-replace-a-hot-water-heater/756541/26 "2016-06-07T16:26:04Z")
> [@guestchaz](#): > > water heaters are “only good for” a decade? > Huh, I always thought they were one of those “20 year durable goods” items. I did not know! > I replaced my 25 year old water heater this spring because the siphon tube disintegrated and clogged up my bathroom faucets (necessitating a new shower valve as well) as well as making me replace the aerator in the kitchen and clean the screen on the washing machine (fuck that pos “dishwasher” my wife swears by) From a cursory look on the Lowe’s website, I see water heaters that are warranteed for as little as 6 years. I didn’t see any for over 10. ---
**Author:** ![Omar\_Little](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/omar_little/32/269_2.png) [@Omar\_Little](https://boards.straightdope.com/u/Omar_Little)\ **Post date:** [June 8, 2016, 12:07pm UTC](https://boards.straightdope.com/t/when-to-replace-a-hot-water-heater/756541/27 "2016-06-08T12:07:31Z")
In some parts of the country, they put hot water heaters in the attic. You sure as hell don’t want to wait until it burst to replace one of those. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [June 8, 2016, 3:25pm UTC](https://boards.straightdope.com/t/when-to-replace-a-hot-water-heater/756541/28 "2016-06-08T15:25:13Z")
> [@Kimballkid](#): > > From a cursory look on the Lowe’s website, I see water heaters that are warranteed for as little as 6 years. I didn’t see any for over 10. That’s like saying that new automobiles are only warranteed from 3 years to at most 5 years. They last much longer than that. ---
**Author:** ![Kimballkid](https://avatars.discourse-cdn.com/v4/letter/k/b5a626/32.png) [@Kimballkid](https://boards.straightdope.com/u/Kimballkid)\ **Post date:** [June 8, 2016, 4:28pm UTC](https://boards.straightdope.com/t/when-to-replace-a-hot-water-heater/756541/29 "2016-06-08T16:28:10Z")
Yes, but they are not and never were meant to be one of those “20 year durable goods” as **guestchaz** was under the impression. [Previous page](https://boards.straightdope.com/t/when-to-replace-a-hot-water-heater/756541.md?page=1)