The entry in brief
An ordinary gas or electric tank usually gives a decade, sometimes fifteen years. A well-descaled tankless unit often outlives that. Hard water and lack of maintenance shorten both.
How to tell the age
Find the silver label on the tank's side. Somewhere in the serial is a code for when it left the factory, often year and month. Manufacturers code it differently, but the year often appears as two digits near the start.
Warning signs
- Water pooling at the base.
- Rusty hot water or rust around fittings.
- Rumbling or popping as it heats.
- Hot water that runs out faster than before.
- A relief valve that drips constantly.
N.B. A leaking tank body cannot be repaired. Shut off the water and gas or power to the heater and arrange a replacement.
Making it last longer
- Run a pail of water out of the drain cock every year to carry the grit away.
- Ask for the anode rod to be pulled and looked at now and then.
- Keep the temperature at a sensible setting, around 49 to 60 degrees Celsius.
- Keep the area around a gas heater clear for air supply.
When to replace
If your tank is over twelve years old and showing any sign above, plan its replacement. Our gas replacement and electric installation pages explain the work.
What callers want to know
Is it worth repairing an old tank?
Replacing a thermocouple or element can be worthwhile. A leaking tank is not repairable.
Does hard water shorten tank life?
Yes. Sediment makes the heater work harder and can lead to overheating at the bottom.