Water Heater Life Expectancy
By Sid Baysinger
Installing and repairing water heaters for almost 40 years has taught me much.
The average water heater life expectancy has diminished over the last 30-35 years.
Thirty years ago you could expect a new water heater to last at least twenty or more years, even without regular maintenance.
How long will your water heater last if you purchase one today?
Tank failure (leaking) is the only reason to trash a unit, everything else can be repaired.
A tank with a six (6) year warranty (most common) should last 10-12 years, without preventive maintenance. Up to 20 years if you keep the sediment flushed out once or twice a year and replace the anode rod every 4 years or as necessary.
You can purchase fiberglass or stainless steel tank type water heaters with life time warranties, however the cost is very high. Upgrading to a gas tankless is a much better choice if you have an existing tank type (traditional) gas water heater, plus you will save up to 40% on your gas bill and most tankless can last up to 25-30 years.
Why does a water heater tank fail?
Hard water mineral sediment collects at the bottom of the tank, this separation of caustic minerals is caused by hot water temperatures exceeding 120 degrees and greater, the minerals form layers at the bottom of the tank in the form of a jelly, after about 18 months or so, this jelly starts to solidify (harden), flushing your tank every 6-12 months will remove this jelly (dirty or acid water as known in the industry) before it's too late.
Under sized water heater for the size of home and or family members has also causes excessive overheating leading to premature tank failure.
High water pressure and/or heat expansion is also a distributing factor in premature tank failure.
These are the most common causes of tank failure, over a period of time the glass liner that was applied to the steel tank at the factory will begin to crack, very fine cracks all over start at first, just like an old china tea cup. Once this glass (china) liner is compromised the water comes in contact with the raw steel tank, at this point the tank begins to slowly rust, if the anode rod is spent (used up) eventually the tank will began to leak.
You cannot repair the water heater if the tank is leaking, the water heater must be replaced.
Which will last longer, gas or electric?
As a general rule, if you place a gas and electric unit side by side on the same water system, the electric unit will survive longer. However, this is not always true. An electric unit could fail many years before a gas unit, all depending on usage and mineral content in your water.
Can a 6-year warranty water heater be made to last longer?
Yes it can. Any model will last longer with proper maintenance, some cheaper models are sold without a sacrificial anode rod. An anode rod (aluminum-magnesium alloy) helps to keep your tank from rusting out. Electro magnetic current always present when water is heated, this magnetic current eats steel like a cancer, however it will attack the sacrificial anode rod first and not your steel water tank, buying longevity.
You can purchase an anode for about thirty dollars. You will want the type that screws into the hot water outlet of your water heater.
Most 6 year warranty water heaters are the same unit as a 12 year model just has a different label attached to it, some do have a second anode rod or other small features but, most are the same.
Follow a regular maintenance schedule (flush the tank every 6 to 12 months) keeping the tank as sediment free as possible.
Remember FLUSH your water heater tank under constant water pressure, not DRAIN with no water pressure, the idea is to stir the mineral settlement at the bottom of the tank and flush it completely out of the tank though the garden hose.
When water is heated, it will expand en average of 20% at temperatures of 125 degrees and greater. Hot water can put enormous pressure on the tank and repeatedly expansion overtime the will eventually
cause tank failure.
To counter this, install an expansion tank above the water heater, this is now required by most codes.
If you follow these guidelines, you should double any water heater's life expectancy.
39 year old Hoyt 1977, Replaced 2016
56 year old RUUD 1959, Replaced 2015