Why we don't give a number of years
You'll see year ranges quoted all over the internet. We haven't found a source we trust that holds across brands, types and water supplies, so we don't publish one.
What we can tell you is what shortens a system's life, and what to watch for.
The anode
Many storage tanks have an anode: a metal rod inside that is meant to wear away so the tank lining lasts longer. Once it's used up, the tank has lost that protection.
Dux, for example, says the anode's "life span is limited and will decrease with the rise in temperature, worsening water quality". We didn't find a manufacturer's check interval to quote, so look in your unit's manual and ask for the anode to be checked when the system is serviced. Our page on elements, thermostats and anodes has more.
Your water
Water quality matters to a tank. Dux designs its heaters for water with Total Dissolved Solids (TDS) under 2,500 mg/L, and its warranty excludes tanks where TDS is higher. It also says that where TDS exceeds 600 mg/L, the magnesium alloy anode may need to be replaced with an aluminium alloy one.
If you're on tank or bore water, tell the plumber. The maker's water quality limits still apply.
In Perth, Water Corporation's advice is that to prevent scale build-up in your hot water system, you should release the pressure valves for a few seconds each month. The water that comes out is hot, so keep your hands and face clear.
Temperature
Don't turn the storage temperature down to make the tank last. The building regulator says Legionella growth is reduced significantly in water stored at 60°C and above, and that turning storage down will promote it. If the taps run too hot, a tempering valve controls the temperature at the bathroom instead.
Signs a system is near the end
- Water leaking from the tank body itself, not a valve or a fitting. See leaking hot water systems.
- Rusty or discoloured water from the hot taps only.
- It needs one part after another.
- Hot water runs out sooner, and a plumber has already ruled out a faulty part.
- The label shows it's older than you thought, and the warranty is long gone.
What "end of life" means in Victoria
From 1 March 2027, a gas hot water system in an existing Victorian home that reaches end of life must be replaced with an efficient electric one (check current rules). We haven't found an official definition of end of life. Repairs are still allowed, so a gas system that can be fixed doesn't have to come out.
For Victorian rentals, the trigger is clearer: the system "permanently fails and can't be repaired".
Age also matters for Solar Victoria's rebate. The system being replaced has to be at least 3 years old from the date of purchase.
Look after the one you have
Find the install date and model
It's usually on the label or in your paperwork. Write it somewhere you'll find it.
Keep the paperwork together
The invoice, the warranty and any compliance certificate. A warranty claim is easier with all three.
Service it as the manual says
Ask the plumber to check the anode and the valves, and to tell you what condition they're in.
Plan the replacement once it's getting old
You'll have time to compare types, check rebates and pick the plumber.
Questions to ask the plumber
- Is this a part that can be replaced, or is the tank itself failing?
- What condition is the anode in, and when should it be looked at again?
- Does our water need a different anode?
- What does the warranty on a new tank cover, and which water conditions void it?
- If it's replaced, which rebates or discounts does its age qualify for?
What we would do
Find the install date this week and write it on the inside of a cupboard door. Once the system is getting on, have a plumber who specialises in hot water check the anode and valves, and decide calmly whether it's worth keeping. Planned, you choose the type and the plumber. After a failure, you take what's available that day.