How long does a hot water cylinder last?
Typical
12 years
Range
10–15 years
Modern unvented (pressurised) cylinders typically last 10–15 years; older vented copper cylinders often manage 15–20. Water chemistry decides most of it — in hard-water areas the immersion element and coil scale up years earlier.
What decides it
- Hard water scaling the coil and immersion element
- Annual service of unvented cylinders (a legal-adjacent norm — pressure valves need checking)
- Sacrificial anode condition in some models
When to replace rather than repair
Leaks from the cylinder body itself are terminal. Valve, thermostat and element failures are repairable.
Typical ranges from manufacturer guidance and industry surveys — individual machines vary with use and care. General information, not advice on a specific appliance.