Repair or replace?
A lot of hot water problems are parts: a valve, an element, a thermostat or a gas igniter. A plumber can often swap the part and get you running again the same day.
Water leaking from the tank itself is different. Once the inner tank lets go, it can't be patched, and the unit needs replacing. Age matters too: an old system that keeps needing parts may be worth replacing on your timetable rather than the day it fails.
Signs it's time to call
- No hot water, or it runs out much sooner than it used to.
- Water pooling under the unit or running down its side.
- Rusty or smelly hot water.
- The gas pilot keeps going out, or the unit trips the power.
- It's old, and you want to plan the next one before it dies.
The main types, side by side
| How it heats | Worth knowing | |
|---|---|---|
| Gas storage | Gas burner under a tank of water | In Victoria, a worn-out gas unit in an existing home must be replaced with an electric one from 1 March 2027 |
| Gas continuous flow | Heats water as it passes through, no tank | The same Victorian rule applies: it covers gas hot water, not just tanks |
| Electric storage | Element inside a tank | In NSW, swapping it for a heat pump can attract an Energy Savings Scheme discount (amounts are indicative) |
| Heat pump | Pulls heat from the air into a tank, like a fridge in reverse | Models under 425 L on the register can earn STCs, a federal discount |
| Solar | Roof collectors heat the water, with a booster | Models under 700 L on the register can earn STCs |
What you can check first
You can
- Check the hot water's switch or circuit at the switchboard is on.
- For gas, check other gas appliances work and the gas is turned on at the meter.
- Read the label on the unit: brand, model and install date. The plumber will ask.
- If it's leaking, turn off the cold water valve to the unit, and the power or gas to it if you can do so safely.
Leave to a licensed plumber
- Anything inside the unit: valves, elements, thermostats, anodes and burners.
- Gas connections and anything that smells of gas.
- Replacing the system, which also brings temperature rules into play.
- Changing thermostat settings. In Queensland, Queensland Health says a licensed electrician should do it.
The temperature rules a plumber works to
Hot water is stored hot for a reason. The building regulator's advice is that Legionella growth is reduced significantly in water stored at 60°C and above, and that turning storage down promotes it.
Hot water reaching bathrooms is a different matter. For fixtures used for personal hygiene, delivery is capped at 50°C, and 45°C in places like aged care and childcare. Kitchens and laundries sit outside the 50°C rule.
Whether a replacement needs a tempering valve depends on your state. Our temperature guide covers each one.
Rebates and discounts
In Victoria, owner-occupiers may get Solar Victoria's hot water rebate on an eligible heat pump or solar system: see Victoria's rebate and discounts. NSW has Energy Savings Scheme discounts, and STCs lower the price of eligible heat pumps and solar anywhere in Australia.
None of them make a new system cost you nothing. Each program expects you to pay something.
Questions to ask the plumber
- Can this be fixed, or is the tank itself gone?
- What size and type suits the people living here?
- Is the new model on the register for STCs, and who claims them?
- Will you fit a tempering valve, and is one required here?
- What does the warranty cover, and for how long?
What we would do
If the unit is leaking from the tank, stop putting money into it and plan the replacement. If it's a part, fix it. Either way, get a plumber who does hot water every week: they carry the common parts, know the rebate paperwork and can tell you honestly which of the two you're looking at.