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If your hot water has gone cold, the usual causes are a tripped circuit breaker or failed element on an electric system, or a pilot light that has gone out or a faulty thermocouple on a gas system. Some of these you can check safely yourself in a couple of minutes. Others need a licensed plumber or gas fitter. This guide walks through the quick checks, the common faults by system type, how long hot water systems last, and how to decide whether to repair or replace.
Call The Plumber Now handles hot water repairs and replacements across Brisbane, Gold Coast, Logan and Ipswich. Here is how to work out what is going on before you book.
Quick checks before you call
A few safe, non-invasive checks rule out the simple causes:
- Check the switchboard. For an electric system, look for a tripped circuit breaker and reset it once. If it trips again, stop and call a plumber. Do not open the unit or touch any wiring.
- Check the gas is on. For a gas system, confirm the gas supply is on and other gas appliances still work. If you can smell gas, turn off the supply, leave the area and call a licensed gas fitter.
- Relight the pilot light. Many gas storage units have a pilot light. Follow the relight instructions printed on the unit itself. If it will not stay lit, the thermocouple may have failed and needs a licensed gas fitter.
- Check the isolation valve. Make sure the cold water isolation valve feeding the unit is fully open.
- Look for leaks. Water pooling under or around the unit points to a tank or valve fault. Note it and mention it when you book.
Never attempt gas or electrical work yourself. In Queensland that work must be done by a licensed tradesperson.
Common causes of no hot water by system type
The likely fault depends on what you have installed.
Electric storage systems
The most common causes are a tripped circuit breaker, a failed heating element or a faulty thermostat. Sediment build-up in the tank over time can also reduce performance.
Gas storage systems
Usual suspects are a pilot light that has gone out, a faulty thermocouple, a gas supply issue or a failed gas control valve.
Continuous flow (instant) gas systems
These have no pilot light on most modern units. No hot water often points to a fault in the ignition, the gas supply, or the internal electronics, and many units display an error code that helps a plumber diagnose the fault quickly.
Heat pump and solar systems
These are more complex. Heat pumps can fault on the compressor, fan or electronics. Solar systems rely on a booster (electric or gas) that can fail while the panels are fine. Both need a plumber familiar with that system type.
How long hot water systems last
Lifespan depends on the type, water quality and how well the unit has been maintained. Hard water and skipped servicing shorten it. These are typical ranges in Australian conditions.
| System type | Typical lifespan |
|---|---|
| Electric storage | About 8 to 12 years |
| Gas storage | About 8 to 12 years |
| Continuous flow (instant) gas | About 15 to 20 years |
| Heat pump | About 10 to 15 years |
| Solar (collectors) | About 15 to 20 years, with the storage tank matching a storage unit |
Regular servicing, including checking the sacrificial anode on tank systems, can add years to any of these.
Repair vs replace: how to decide
A single failed part on a unit that is only a few years old is usually worth repairing. Once a system is near the end of the ranges above, or the repair is a large one like a leaking tank, replacement often makes more sense. Use this as a guide.
| Situation | Lean towards |
|---|---|
| Unit is under about 8 years old, minor fault (element, thermostat, thermocouple) | Repair |
| Unit is near or past its typical lifespan | Replace |
| Tank is leaking from the body of the cylinder | Replace |
| Repeated breakdowns in a short period | Replace |
| Repair cost is a large share of a new system | Replace |
Hot water repairs with Call The Plumber Now range from $250 to $1,500 depending on the fault and parts required, in line with our Brisbane plumber cost guide. New system cost varies with the type and size you choose, so the best step is to get a quote for your situation. See our hot water repairs and hot water installations pages for what each involves.
Hot water and the 50C tempering valve rule
Australian plumbing standards require that hot water delivered to bathroom taps, showers and other outlets used for personal hygiene must not exceed 50 degrees Celsius. This is done with a tempering valve or thermostatic mixing valve fitted to the hot water line.
The tank still runs hotter than that on purpose. Water is stored at 60 degrees or above to control Legionella bacteria, then the tempering valve blends it down to a safe 50 degrees at the outlet. This limit reduces the risk of scalding, which matters most for children and older people. Under the standards, a compliant tempering valve must be fitted whenever a new system is installed or an existing one is replaced, so it is part of any proper installation.
Why use a licensed local plumber
In Queensland, installing or replacing a hot water system is regulated plumbing work and must be carried out by a QBCC-licensed plumber. If the system runs on gas, the work also requires a gas work licence, which is separate from a plumbing licence. Unlicensed hot water or gas work is illegal, unsafe and can void your insurance.
Call The Plumber Now is a local team working across Brisbane, Gold Coast, Logan and Ipswich. We diagnose the fault, tell you honestly whether a repair or a replacement is the better call, and fit a compliant tempering valve on any new install. For a system with no hot water and no clear cause, our emergency plumbing team can attend quickly.
Frequently Asked Questions
How long do hot water systems last?
It depends on the type. Electric and gas storage units typically last about 8 to 12 years, heat pumps about 10 to 15 years, and continuous flow gas and solar collectors around 15 to 20 years. Water quality and regular servicing make a real difference to how long any unit lasts.
Why do I suddenly have no hot water in Brisbane?
The common causes are a tripped circuit breaker or failed element on an electric system, or a pilot light that has gone out or a faulty thermocouple on a gas system. Check the switchboard and the gas supply first. If those look fine, book a plumber to diagnose it.
Should I repair or replace my hot water system?
Repair usually makes sense for a minor fault on a unit under about 8 years old. Replace when the unit is near or past its typical lifespan, the tank itself is leaking, it keeps breaking down, or the repair costs a large share of a new system.
How much does a hot water repair cost?
With Call The Plumber Now, hot water repairs range from $250 to $1,500 depending on the fault and the parts needed. New system replacement cost varies with the type and size, so it is best to get a quote.
Do I need a licensed plumber to replace a hot water system in Queensland?
Yes. Installing or replacing a hot water system is regulated plumbing work in Queensland and must be done by a QBCC-licensed plumber. Gas systems also require a separate gas work licence.
Book a hot water plumber in South East Queensland
If you have no hot water, or your system is getting on in years and you want to know your options, Call The Plumber Now can help across Brisbane, Gold Coast, Logan and Ipswich. We will diagnose the fault, give you a straight answer on repair versus replace, and quote the work up front. Get a quote today.
