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How you know your electric water heater is dying

As some of my long-time readers know, we have 2 water heaters in our home thanks to the prior owners. One is a 40 gallon gas water heater upstairs that is for everything except the “new” bathroom the added. The 2nd bathroom has its own 30 gallon electric water heater. Why? I don’t know, but it has been convenient when we have a lot of guests visiting and needing showers at the same time.

You may also recall that we each have “our own” bathrooms. The gas-heated one is mine and the electric one is hers.

When my wife started to seriously complain that her showers weren’t staying hot, then I started to listen. I knew the heater was going on 13 years old, but I didn’t know how long water heaters lasted. Well I do now.

Luckily, we have an expert handyman in our family (her father), and he told me what to check on the heater to see if something what broken.

Some basics about your electric water heater

I’m not going to try to come across as any expert, but here’s what I was instructed about our water heater plus some things I learned later:

  • It has 2 heating elements: one on top and one on the bottom
  • If you want to check whether the heating element is broken, you need an Ohm reader (Multimeter) to test the current. Multimeters are also good to test electrical sockets, such as voltage, whether they’re alive or not, etc.
  • Water heaters generally come with warranties of 6, 9 or 12 years. Based on that, even if the last owners bought the best one, we’re past the warranty, but I’m guessing they have a 6 year. Why? Because I can’t find 30 gallon electric tanks with more than 6 year warranties.
  • 12 year warrantied heaters seem to have steel heating elements rather than copper (or vice versa). 9 year have one of each.

How to test whether the heating element is still working:

  1. Turn off the breaker to the water heater
  2. Open up the plate to access the element. There may be plastic and insulation covering it. It’s the thing with the large hexagonal nut behind it (if there’s another unit, it’s probably the thermostat).
  3. Use your multimeter to test whether there is voltage going to the red and black wires. If so, you didn’t turn off the power properly.
  4. Once power is confirmed off, remove the red and black wires from the element.
  5. Switch your multimeter to read Ohms and touch the red point to the red terminal (screw) and the black to the black.
  6. If the reading is very low or nothing, then the element is not working. It means it’s rotted and the U-shaped element is no longer U-shaped and thus not sending a current properly. If you get a reading, then the element is good.
  7. Test the other element in the same way, but don’t forget to hook the red and black wires back up properly and replace the insulation and cover on the other element.

If it’s not the heating elements, well then I can’t help any more.

The quick way I found out our heater was dying:

The first element I went to test was the bottom one since that’s where all the sediment ends up and corrodes the element faster. When I took off the outer cover and removed the fiberglass insulation, I found it was damp on the inside and soaked on the bottom inch. I thought “UH OH!”. I put my finger down in the pan under the heater and felt water. Just a little bit, but enough to tell me it’s time to get a new water heater.

The final nail in the coffin? The severe amount of corrosion around the element showed we didn’t even have the option to replace the element. If it wasn’t corroded, we could have drained the tank and replaced it for $20-30. But not now. We’re lucky my wife noticed a difference, her dad was experienced enough to figure it out and that the tank didn’t rupture (yet).

I did end up buying a new 9 year, 40 gallon water heater which we’ll install very soon. Unfortunately, our state has a new code that requires an expansion tank be installed, so that was an extra cost. Plus, you need to have a building permit to install the tank, at least in our county in Maryland. Overall, the tank I chose and the expansion tank cost about $425, but if I wanted to be sneaky and cheap, I could have done it for half the price myself. I don’t recommend going cheap or against the law.

About the author

Clever Dude

5 Comments

  • For what it is worth, this all could have been prevented. A little known (and rarely practiced) preventative measure could have given your water heater virtually indefinite life.

    This preventative maintenance step is to check the sacrificial anode that is usually installed through the top of the tank. It’s a simple procedure that almost anyone can do. The sacrificial anode is a long rod or series of rods that are meant to be consumed by the electrolysis process instead of the process eating away at the tank itself. Different tanks, water quality, water temperature and amount of use will all be factors that determine how quickly these anodes will be consumed. Once the anode is consumed, then the electrolysis process will begin eating at the tank, eventually resulting in a tank failure. But if you check your anode at a regular interval (I check mine every two years), you can replace it and save yourself the headache later. The best part about this is that the anode is really cheap (like $15).

    To check, look at the top of your tank. From the outside, it looks like a large hexagonal(?) nut. Simply unscrew this nut and pull out the sacrificial anode. Depending on how much of the anode is remaining, you may want to replace it.

    Of course I only gave a very brief description, but a quick Google search pulls up some great reads and pictures:
    http://www.waterheaterrescue.com/pages/WHRpages/English/Longevity/water-heater-anodes.html

  • @Rob, thanks for the explanation to the readers. I did know about the sacrificial rod (thanks to Ask This Old House), but was too lazy to check it. If I had known back when I bought the house, we could have saved it, but definitely not in the last couple years as it had already been at work on the elements.

    My biggest concern right now is our 40-50 gallon gas tank (I have to check again) in our upstairs that’s way too old and could go any day. At this point I’m afraid that if I check the rod, it would break something and we’re not ready to replace that one yet.

  • @FASydney, it’s easier said than done to “go solar”. Even with the federal, state and local tax credits and incentives, the payback period for solar is horrendous. Plus, there’s no “solar water tank” except for those powered by solar (which has to be converted to electricity anyway and we’re back at square one).

    If we wanted to reduce our risk with life of our water tanks, we should go “tankless”, which go for 20+ years. Unfortunately, they’re much more expensive and, from what I’ve heard recently, at least the electric ones suck up huge amounts of power to heat the water quickly compared to the slow heating from a water tank.

  • I wish I would have noticed this article last month when I had issues with my hot water heater. However I found so much diy fix it info and pdf manuals on hot water heaters my 15 yo cousin and I fixed my hot water heater a couple of weeks ago and it’s blazing along like gangbusters now. The thermostats were bad but we bought a kit at Home Depot for 32 bucks for a dual element hot water heater and changed out everything in order to be proactive.

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