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How long does a water heater last?

How long does a water heater last? For most homes the answer is 8 to 12 years for a conventional tank water heater, and 20 years or more for a tankless model that gets regular maintenance. Where your unit lands in that range depends heavily on your water quality, how you use it, and whether it has been maintained — a neglected tank can fail in six or seven years, while a well-cared-for one can push past a decade.

Typical lifespan by type

These are general ranges, not guarantees. Electric tanks often edge out gas tanks slightly because they have no burner or flue to corrode, but water quality and maintenance matter more than the fuel type.

What shortens a water heater's life

Two identical heaters can be a decade apart in how long they last. These are the biggest factors that cut a unit's life short:

• Hard water and sediment. Minerals in hard water settle as sediment on the bottom of a tank. That layer traps heat against the steel, makes the unit work harder, and speeds up corrosion.
• Skipped maintenance. A tank that's never flushed and never inspected builds sediment and hides small problems until they become leaks.
• A worn-out anode rod. The sacrificial anode rod is designed to corrode instead of the tank. Once it's used up — often within a few years — the tank itself starts to rust.
• High usage. A large household drawing hot water all day puts more cycles on the unit than a couple in a small home, and it wears out sooner.
• No expansion tank. On a closed plumbing system, thermal expansion with no expansion tank stresses the tank and fittings with every heating cycle.

Warning signs it's failing

A water heater rarely dies without warning. Watch for these signs, especially as the unit approaches its typical age range:

• Rusty or discoloured hot water. Brown or reddish water from the hot tap (but not the cold) usually means the tank is corroding from the inside.
• Rumbling or popping noises. That's the sound of the burner heating through a thick layer of hardened sediment — a sign of lost efficiency and added stress.
• Leaks or moisture around the base. Water pooling under the unit often means the tank has cracked. A leaking tank can't be repaired — it needs to be replaced.
• Running out of hot water faster. If showers turn cold sooner than they used to, sediment may be crowding out the tank's usable capacity.
• Age near or over the range. If you don't know how old it is, check the serial number on the label — the first characters often encode the manufacture date.

How to extend its life

A little upkeep goes a long way. To get the full lifespan out of a water heater:

• Flush the tank annually to clear out sediment before it builds up.
• Check the anode rod every few years and replace it when it's heavily corroded — a cheap rod can save the whole tank.
• Set a sensible temperature of around 120°F (49°C). Hotter settings speed up corrosion and mineral buildup (and raise the scalding risk).
• Install an expansion tank if your system is closed and doesn't already have one, to absorb thermal expansion.

Repair or replace?

The right call usually comes down to the unit's age and what's actually wrong:

• Replace it if the heater is near the end of its typical life, or if the tank itself is leaking. Leaks from the tank body can't be fixed, and pouring money into an old unit rarely pays off.
• Repair it if the unit is still relatively new and the problem is a single component — a faulty thermostat, a burned-out heating element, or a bad valve. Those are inexpensive fixes on a heater with years of life left.

As a rule of thumb, once a tank heater is past about 10 years, put repair money toward a replacement instead — a new, more efficient unit will usually cost less over its lifetime than repeated fixes on an aging one.

Frequently asked questions

How do I know if my water heater is going bad?

Watch for rusty or discoloured hot water, rumbling or popping noises from the tank, moisture or pooling water around the base, and hot water that runs out faster than it used to. Any of these on a unit near or past its typical age range is a strong sign it's on the way out.

Does flushing a water heater extend its life?

Yes. Flushing the tank once a year clears out the mineral sediment that settles on the bottom. Sediment makes the burner or element work harder and traps heat against the steel, which accelerates corrosion — so regular flushing is one of the simplest ways to add years to a tank heater.

Is a tankless water heater worth it?

Tankless units cost more up front and often need a larger gas line or electrical upgrade, but they typically last 20 years or more — roughly double a tank heater — and only heat water on demand. If you plan to stay in the home long term and keep up with annual descaling, the longer lifespan and endless hot water often make them worth it.

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