Most water heaters give plenty of warning before they fail. Knowing roughly how long yours should last, and what shortens that, tells you whether a strange noise is a service call or the start of a replacement plan.
1. A tank heater: eight to twelve years
A conventional storage tank usually lasts eight to twelve years. The steel inside is protected by a sacrificial anode rod; once that rod is used up, the tank itself starts to corrode, and from then on it is a matter of time.
2. Tankless and combi units: fifteen years or more
With no stored water sitting against steel, tankless heaters and combi boilers often run well past fifteen years. What ends them is usually scale on the heat exchanger or a failed part that is no longer worth replacing.
3. Hard water takes years off
In a hard water area, scale settles at the bottom of the tank and insulates the water from the burner or element. The heater works harder, makes more noise and wears out sooner. An annual flush and a softener can add years.
“Replacing the anode rod at the five-year mark costs a fraction of a new heater, and it is the single best thing you can do for a tank.”
4. The signs it is near the end
Rusty water from the hot taps, a damp patch or slow drip under the tank, rumbling that a flush no longer cures, and hot water that runs out sooner every month all point the same way. A leak from the tank body itself cannot be repaired.
5. Repair or replace?
If the unit is under eight years old and the fault is a thermostat, element or valve, a repair is usually the better spend. Past ten years, or with any sign of corrosion on the tank, put the repair money towards a correctly sized replacement instead.
