How Long Does a Hot Water System Last? (And When to Replace It)
Most Melbourne homeowners don’t think about their hot water system until it fails — usually at the worst possible time. Knowing the expected lifespan of your system helps you plan a replacement before you’re left with cold showers.
Hot Water System Lifespans by Type
- Electric storage hot water system: 10–15 years
- Gas storage hot water system: 10–15 years
- Gas continuous flow (instantaneous): 15–20 years
- Heat pump hot water system: 10–15 years
- Solar hot water system: 15–25 years (panels may outlast the storage tank)
These are average lifespans under normal Melbourne conditions with regular maintenance. Hard water, high usage, and poor installation all reduce lifespan.
5 Signs Your Hot Water System Needs Replacing
1. It’s over 10 years old and needs regular repairs
One repair on an older system is often reasonable. Two in 12 months is a warning sign. If the repair cost is more than 50% of what a new system would cost, replacement usually makes more financial sense.
2. Water from the tank is rust-coloured or smells off
Brown or rusty water from hot taps (not cold) usually means the tank’s anode rod has failed and the tank itself is corroding internally. This is not fixable — the tank needs replacement.
3. The tank is visibly leaking from the base
A small amount of water near the pressure relief valve discharge pipe is normal. Water pooling under the tank itself means the tank wall has cracked — irreparable.
4. You’re running out of hot water faster than you used to
Sediment build-up at the bottom of electric and gas storage tanks reduces effective capacity over time. If your 250L system used to easily cover the household but now runs out, sediment is likely the cause.
5. Your energy bills have increased without explanation
An ageing hot water system works harder to reach temperature, using more gas or electricity. Replacing an old electric storage system with a heat pump or continuous flow gas system can significantly reduce your bills.
Repair or Replace?
As a rough rule: if your system is under 8 years old, repair. If it’s over 12 years old and the repair cost is significant, replace. Between 8–12 years, get a plumber to inspect and advise.
Melbourne Hot Water System Replacement
Sedcon Plumbing supplies and installs all major brands across Melbourne — Rheem, Rinnai, Bosch, Dux. We can advise on the right system for your household size, gas/electric availability, and budget. More about our hot water service · 2025 cost guide for hot water replacement.
Call 0468 013 012 · VBA Licence 120392