May 17, 2016 / Apple Plumbing, Water Heaters

I’m often asked “When should I replace my water heater?” or “When will my water heater fail?” The answer to both questions is “I don’t know! But I can give you and educated guess”.
By a failing water heater I mean a water heater that starts leaking. A leaking heater cannot be repaired…not ever. If a heater stops producing hot water, then it most likely can be fixed. But if it leaks, it is dead.

So, should a homeowner just wait until a heater starts leaking to replace it? No. There are some educated assessments that can be made. First, how old is the heater? Every heater has a sticker on it that gives some important information like the size (gallons), the energy source (electric, natural gas, propane gas, etc…), energy input (watts, btu’s, etc…), model number and serial number. With the model number and serial number a person can get online with the manufacturer’s website and find the date the heater was produced. Most water heaters take 3 months from the time they are manufactured until they are installed in a home.

We see most water heater failures in the 10-12 year old range. The oldest water heater I have replaced was 35 years old. It hadn’t failed, it just needed a new gas valve that was no longer available.

What I usually tell customers is:

  • If your water heater is 10 years old, it owes you nothing and you shouldn’t be surprised if it starts leaking
  • If your heater is 15 years old you can expect it to fail any time
  • If your heater is 20 years old, failure is imminent and you should replace immediately

My theory is that if a water heater hits 10 years, it should be replaced soon. Why wait for a possible flood? You don’t ride on your car tires until they blow out do you? Once tires hit the recommended mileage, we generally replace them. Same with a water heater. Once it hits the expected life time, change it.

Another reason to consider preemptively replacing a water heater is energy usage. I read an article the other day that quoted a trade magazine saying that every inch of sediment in a water heater requires 70% more energy to heat the water.

Every heater has some sediment in it. It’s a natural result of heating water. Some sediment is calcium from hard water, some is sediment from a well, and some is just particulates suspended in water. Any sediment in water just sitting in a heater tank will settle to the bottom. No avoiding it. Flushing out your heater annually will keep the sediment at bay. However, if you haven’t been doing that, then your heater probably has a fair amount of sediment in it. The more sediment there is, the more difficult it can be to flush it out. Sediment can also cause undue stress on the steel tank of a gas water heater.


The gas burner on a heater heats the bottom of the tank. A build-up of sediment insulates the bottom of the tank causing the burner to run longer and heat the steel to a higher temperature than normal. This higher heat stresses the steal causing premature failure.

With electric water heaters, sediment can build up to the point where it completely encompasses the lower element insulating it from the water to be heated.  More energy wasted.

There are maintenance items that can be done to extend the life a water heater. More on that next time!

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