Hot water system replacement: repair or replace?
Updated 28 Oct 2026
A leaking tank means replace. A working tank with one failed part usually means repair.
Replace a hot water system when the tank leaks, the water runs rusty, or it keeps failing. Repair it when the tank is sound and one part has failed. A licensed plumber can tell you which, and a leaking tank cannot be patched.
Is my hot water system leaking? Is it a plumber job?
Look first. Don't open the unit.
Hot water system leaking from the bottom
Water pooling under the tank, or dripping from the base, usually means the tank has rusted through. Turn off the power or gas, close the cold tap on the pipe going in, and call. If water is spreading, see emergency plumbing.
A drip from the pipe on the side
A small drip from the relief valve pipe can be normal while the tank heats. A steady flow is not. If you are unsure, it is a plumber job.
Not sure which one you have? Ask a licensed plumber to look.
When should I replace my hot water system?
| What you see | Usually means |
|---|---|
| Water leaking from the tank or its base | Replace. The tank has failed. |
| Rusty or brown hot water | Can be a rusting tank. Replace, once a plumber confirms it is not the pipes. |
| Repairs again and again | Replace. Each repair is money into a tired system. |
| Not enough hot water for the household | The tank may be too small now. A bigger or different system may suit better. |
| No hot water, tank dry and sound | Can be a repair: a thermostat, element or valve. |
For quick checks on a system that has stopped, see our hot water repairs and replacement page.
How long does a hot water system last?
How long a tank lasts depends on the make, your water and how well it was installed. Check your warranty and the date on the rating label.
Age alone is not a reason to replace. An older tank that runs fine can stay. An older tank that leaks or keeps failing should go. Replacing it before it floods the cupboard can be the calmer choice.
Which hot water system should I choose?
| System | Good | Watch |
|---|---|---|
| Electric storage | Simple. Easy to fit in a typical home. | Costs more to run than a heat pump. |
| Gas storage | Works with gas. | Needs gas and a safe flue. |
| Gas continuous flow | Heats as you use it, so it doesn't run out. Compact. | Needs gas and a flue. Some units can't take one. |
| Heat pump | Uses less energy than electric storage. | Needs outdoor space, airflow and some noise allowance. |
| Solar | Uses the sun for some of the heating. | Needs roof space and sun. Usually has a booster. |
The hot water hub has more on what suits a house or a unit.
Are there NSW incentives for heat pumps?
The NSW Government lists an upfront discount for replacing an old water heater with an eligible heat pump. It comes off the installer's quote. The installer must be licensed, and only listed models qualify. Amounts and rules change, so ask about current NSW energy incentives before you sign.
Gas work needs a licence
In NSW, a gas system must be fitted by a licensed gasfitter. Switching away from gas also needs one. See gas plumbing.
Why use a licensed plumber to replace a hot water system?
Hot water work involves water pressure, power or gas, and a hot tank. In NSW it needs a licence. A licensed plumber has the equipment to fit it safely and to connect it to the right standard.
Ask for a compliance certificate for the work. If water from the unit has damaged your home, ask your insurer if they need a plumber's report.
Hot water replacement on the Northern Beaches
Your home changes what fits.
- Mona Vale has houses, units above the shops and cafe kitchens: hot water in Mona Vale.
- Freshwater flats can keep the unit in a cupboard or on a balcony. Ask where a new one can go: hot water in Freshwater.
- In Manly, outdoor units sit in salty air. Rust at the base is the warning: hot water in Manly.
- Dee Why units can keep the system on a balcony or in a small cupboard. A replacement has to fit, and in strata you ask first: hot water in Dee Why.
What changes the price of a hot water replacement?
| Factor | Why it matters |
|---|---|
| System type | A heat pump, solar or continuous flow system costs more than a basic tank. |
| Size | A bigger household needs a bigger system. |
| Swapping type | Gas to electric, or the reverse, needs extra pipe, wiring or a flue. |
| Access and space | A tight cupboard or balcony takes longer. |
| Time of day | Nights and weekends usually cost more. |
Each plumber sets their own price. Ask for it before work starts. Asking is free.
Hot water replacement questions
Can I replace a hot water system myself?
No. In NSW, hot water installs and gas work need a licensed plumber.
Why is my hot water system leaking from the bottom?
Usually the tank has rusted through, and it can't be patched. Turn off the power or gas, close the cold tap and call a licensed plumber.
How long does a hot water system last?
It varies with the make and your water. A leak or repeated faults matter more than age alone.
Can I get a NSW rebate for a heat pump?
The NSW Government lists an upfront discount for eligible heat pumps, taken off the installer's quote. Rules change, so ask about current NSW energy incentives.
Will my landlord or insurer cover it?
If you rent, tell your landlord or agent first. Hot water is usually theirs to fix. If you own, check your policy, as some cover sudden damage and not a worn-out tank.
Weighing up a new system? Tell us about your home and a licensed plumber can talk through what fits.
Get a hot water callback
A licensed plumber calls you to book a time that suits.