Water Heater Question

[Chainfire]

9. I am an old retired plumber, so I will attempt to teach WH-101

This may be one of the questions I never had to answer in my plumbing career.

What generally kills a water heater is hard water. Deposits build up on the sides of the tank and on the elements. When the deposits cover the elements, they burn out because they don't have water to cool the element and they literally melt into. Even without the sediment, the elements wear out like just like light bulbs or stove elements. More people in the house would cause the elements to burn out faster, for the same reason, it would also shorten the life of the tank, but I don't think substantially.

When elements burn out, they can be replaced. The cost to replace the elements will probably be about 25% of the cost to replace the whole unit. When the tank fails the heater is DOA. Tanks usually fail slowly, which is very good; they will usually develop what we call pin-holes, or sand-holes and may fail with a drip, a fine mist, or steam.

To give you a straight answer to your question, it is my opinion that all other things being equal, that a water heater will last longer with less usage.

As far as guesswork as to how long you should expect a water heater to last, it would take a crystal ball. I have worked on water heaters that were 40 years old, and I have seen them fail after a few months of usage. Generally they will last ten to fifteen years. Interestingly, I have never seen a difference in really expensive brands and lesser expensive brands. When you buy a water heater, buy based on the energy ratings alone.

I hope that helps.