Hot Water System Leaking? What to Do Now, and Whether It Can Be Fixed
Not every drip is a problem: a small discharge from the relief valve while the tank heats is normal. But a leak from the tank itself can't be repaired, and it usually gets worse. Here's how to stop the damage, work out where the water is coming from, and what it costs either way.
Leaking tank? Get up to 3 replacement quotes from licensed local installers, free.
Get free installer quotes- Free, no obligation
- Licensed local installers
- We are paid by installers, never by you
Don't relight or reset anything, don't use electrical switches, put out any flames and get everyone outside. If it's safe, turn the gas off at the meter (or the cylinder for LPG). Then call your gas distributor's emergency line from outside, or 000 if anyone is in danger.
Gas emergency numbers by area
- Victoria: Multinet Gas (inner and outer east Melbourne, Yarra Ranges, South Gippsland), 132 691
- Victoria: Australian Gas Networks (north and south-east Melbourne, northern and eastern Victoria), 1800 427 532
- Victoria: AusNet Services (central and western Victoria), 13 67 07
- New South Wales: Jemena (Sydney and most of New South Wales), 131 909
- New South Wales: Australian Gas Networks (parts of regional New South Wales), 1800 427 532
- ACT: Evoenergy, 13 19 09
- South Australia: Australian Gas Networks, 1800 427 532
- Western Australia: ATCO Gas Australia, 13 13 52
- Tasmania: Tas Gas Networks, 1802 111
- Queensland, Northern Territory and LPG: use the emergency number on your gas bill, or on the cylinder or tank.
Numbers from the distributors' own pages and Energy Safe Victoria: gas emergencies, checked 13 October 2026.
1. Stop the Damage
- Electric, heat pump or solar: switch off the HOT WATER switch at the switchboard, and the isolating switch at the heater if there is one.
- Gas storage: turn the gas control knob to OFF.
- Then close the cold water valve on the pipe going into the heater, so the tank stops refilling. On a gas unit, then close the gas valve on the heater's supply line.
- Keep clear of the relief valve drain: the water can be very hot.
Shut-down steps from the owner guides: Rinnai 4 Star gas storage owner guide, Solahart owner guide (September 2025), Rinnai Enviroflo heat pump owner guide and Dux hot water troubleshooting guide.
2. Where Is the Water Coming From?
Usually normal. Water expands as it heats, and the valve lets a little out: roughly 1/50 of the hot water you use. Never block the drain line.
Needs a plumber.It can mean high mains pressure, a faulty valve or a thermostat problem. For a dribble, the makers suggest gently lifting the valve's easing lever for a few seconds and lowering it gently, which can clear grit from the seat. If it keeps dribbling, call a plumber. A relief valve replacement typically costs $150 to $300.
Switch the heater off now. This points to an overheating fault, usually the thermostat. It needs a licensed plumber or electrician.
Usually repairable. A minor leak at a fitting typically costs $150 to $400 to fix.
Means replacement. Once the inner cylinder corrodes through it can't be repaired. Get a plumber to confirm it's the tank and not a fitting, then compare replacement quotes.
Usually condensate, which drains away outside the unit and is normal.
From the owner guides: Rinnai 4 Star gas storage owner guide, Solahart owner guide (September 2025), Rinnai Enviroflo heat pump owner guide and Dux hot water troubleshooting guide. Repair costs from 2026 cost guides (table below).
Prevent the next one:the makers ask owners to gently ease the relief valve lever every six months, and to have a licensed plumber replace the relief valve and check the anode at least every five years. Skipping it can shorten the tank's life.
Anything inside the unit, any gas part and any wiring is a job for a licensed plumber, gasfitter or electrician. In New South Wales all plumbing and gasfitting work needs a licence (NSW Government: plumbing, draining and gasfitting work), and in Victoria unqualified electrical work is illegal (Energy Safe Victoria: electrical work you must not do yourself).
What Leak Repairs Cost
| Repair | Typical cost |
|---|---|
| Call-out and diagnosis Capital Plumbing $80 to $150; The Quote Yard $100 to $180 in Melbourne | $80 - $180 |
| Electric element The Quote Yard $250 to $500 ($280 to $550 in Melbourne); Capital Plumbing $200 to $450 | $200 - $550 |
| Thermostat (electric) The Quote Yard $200 to $400; Capital Plumbing $150 to $350 | $150 - $400 |
| Thermocouple or ignition (gas storage) The Quote Yard $150 to $350; Capital Plumbing $200 to $500 or more | $150 - $500 |
| Gas control valve $400 to $800 in Melbourne | $200 - $800 |
| Relief valve (TPR) | $150 - $300 |
| Anode What's The Damage $200 to $500 nationally, $210 to $525 in Melbourne; The Quote Yard from $150 | $150 - $525 |
| Minor leak at a fitting | $150 - $400 |
| Continuous flow circuit board $300 to $600 for the part plus $150 to $250 labour | $450 - $850 |
| Heat pump component | $300 - $1,000 |
Published 2026 ranges from The Quote Yard, hot water system repairs Victoria 2026 (published 24 Aug 2026), Capital Plumbing, hot water system repair cost (21 Jul 2026) and What's The Damage, hot water system cost (October 2026). Indicative only: your plumber's quote decides.
No water at all rather than too much? See hot water not working: what to check.
Repair or Replace?
Repair a younger system with a single failed part. Replace it if the tank itself is leaking, the system is past about three quarters of its expected life, or the repair would cost more than half a new unit. (rule of thumb from The Quote Yard, hot water system repairs Victoria 2026 (published 24 Aug 2026).)
| System | Typical life |
|---|---|
| Electric storage | 8 to 15 years |
| Gas storage | 8 to 12 years |
| Heat pump | 10 to 15 years |
| Gas continuous flow | 15 to 20 years (Canstar says more than 20) |
From The Quote Yard, hot water system repairs Victoria 2026 (published 24 Aug 2026), Capital Plumbing, hot water system repair cost (21 Jul 2026) and Canstar: hot water systems. Solar Victoria: choosing a hot water system puts the typical life of a hot water system at 8 to 10 years. The manufacture date is on the compliance plate on the side of the unit.
Replacing anyway? See what a hot water system replacement costs, or compare Rheem, Rinnai, Thermann and Dux prices.
Leaking gas tank in Victoria? From 1 March 2027, Victorian law requires a mains gas hot water unit that fails in an existing home to be replaced with an electric one. Limited exemptions apply, for example where there is no room for an electric unit. What replacing gas hot water in Victoria costs.
Frequently Asked Questions
Is it normal for a hot water system to drip?
A small drip from the relief valve drain while the tank is heating is normal, because water expands as it heats. Rheem and Solahart put it at roughly 1/50 of the hot water you use. More than about a bucket in 24 hours, a constant dribble, or hot water pouring out until the tank goes cold is not normal and needs a plumber.
Can a leaking hot water tank be repaired?
A leak from a fitting, pipe or valve can usually be repaired, often for $150 to $400. A leak from the tank body itself, where the inner cylinder has corroded through, cannot be repaired and means replacing the system. A plumber can tell you which one you have.
What should I do first if my hot water system is leaking?
Turn off the power to an electric, heat pump or solar system at the switchboard, or turn the gas control to OFF on a gas unit, then close the cold water valve on the pipe going into the heater. That stops the tank refilling and limits the damage while you arrange a plumber.
Is water around a heat pump a leak?
Usually not. Heat pumps and some high-efficiency gas units produce condensate that drains away outside the unit, so some water nearby is normal. Water coming from the tank, a fitting or the relief valve is a different matter.
Does the warranty cover leak damage?
A failed tank is often covered for the cylinder itself, but water damage to the property usually is not. Solahart, for example, excludes damage caused by leakage, which is why manufacturers recommend a safe tray with a drain where a leak could damage the home. Your rights under the Australian Consumer Law still apply.
Can I replace a leaking gas hot water system with gas in Victoria?
Until 28 February 2027, yes. From 1 March 2027, Victorian law requires a mains gas hot water unit that fails in an existing home to be replaced with an electric one. Limited exemptions apply, for example where there is no room for an electric unit. Repairs to an existing gas unit are still allowed.
What are you replacing?
Tap one to continue