GerardThere’s nothing worse than turning on the tap, expecting a hot shower to start your day, only to be hit with freezing cold water instead.
Whether it’s the first thing in the morning or after a long day, no hot water is super inconvenient and can disrupt your routine, household, or business.
The good news? Having no hot water doesn’t mean your system is completely cooked.
Some issues are straightforward to fix and can be resolved in 5 minutes. Others may need a licensed plumber.
This guide walks you through the most common causes of what causes no hot water, what’s safe to check yourself, and when to pick up the phone.
Start With These Steps Before You Call Anyone
Before assuming the worst or tearing apart your system, run a few quick checks and call a plumber only if necessary. Who knows, it might be something as simple as a blown fuse or an empty tank. Run through these quick fixes first.
Do you have an electric system? Check your switchboard.
If you’ve got no hot water and you’ve got an electric hot water system, head to your switchboard. A tripped circuit breaker or blown fuses are common culprits.
If the breaker has tripped, reset it once. If it trips again straight away, this is a sign of an electric water heater malfunction.
Do not keep resetting the breaker. If you keep resetting it, electricity is being forced back through a system that isn’t working properly. This can cause further damage, increase the risk of electrical faults, or, in some cases, create a fire hazard.
At this point, you should call a qualified plumber to inspect and safely repair the issue.
Do you have a Gas system? Check your supply.
If your appliances, such as a gas stove, are working but your hot water isn’t, the next step is to check whether your system is trying to ignite. Listen for clicking sounds or look for any error codes on the unit if it has a display.
If your unit has a display code, search for it using the system’s brand to get more information.
If there’s no ignition, the issue could be with the pilot light, the thermocouple, or the ignition system. If you smell gas at any point, turn off your gas supply immediately, avoid using electrical switches or appliances, and leave the area. Once safe, contact a licensed gas fitter or emergency services.
At this stage, do not attempt to open or repair the unit yourself. Gas systems should be handled by a qualified professional. A licensed plumber can safely inspect the system, identify the fault and get your hot water working properly again.
Could the tank just be empty?
Storage systems have a finite amount of hot water. If your property has been using more hot water than usual, your tank may simply need time to heat the water again.
Electric systems typically take one to two hours to fully recover. Gas systems are faster, usually around 30 to 60 minutes. If the water comes back on its own, problem solved.
Common Reasons You Have No Hot Water
If the basic checks didn’t reveal anything obvious, one of these is likely the cause.
1. Faulty Heating Element (Only for electric systems)
A faulty heating element is common in electric systems. Over time, heating elements can wear out or get coated in mineral build-up (which is common in Perth). When that happens, they can’t heat the water properly.
When heating elements aren’t operating at full efficiency, they can’t heat water properly. You might notice the water temperature drops off quickly, or you’re only getting lukewarm water instead of actually hot water.
A faulty heating element isn’t something you should test or replace yourself. It requires the right tools and a licensed tradesperson. If your system is more than 8 years old, this is a likely suspect.
2. Tripped or Faulty Thermostat
A faulty thermostat can cause problems, from inconsistent water temperature to no hot water at all.
In some cases, the thermostat trips as a safety measure when the system overheats. While that sounds like it’s doing its job, it also means your system isn’t working properly and needs attention.
A plumber can test the thermostat and replace it if needed. We recommend not adding this to your DIY list, as it could interfere with the wrong component and risk making the problem worse or creating a safety hazard.
3. Gas Supply or Ignition Failure
If you have a gas system and you’re getting no hot water, the issue can be tied to ignition or the gas supply.
Common signs include:
- No visible flame when the system tries to fire
- A clicking sound, but no ignition
- Error codes appearing on the unit’s display
These symptoms usually point to a problem with the pilot light, thermocouple, or ignition system. Issues with the gas lines themselves can also cut your supply entirely.
4. Leaking or Failing Hot Water Tank
If you’ve noticed:
- Water pooling around your system
- Reduced water flow
- Rusty-looking water coming from your taps
- Inconsistent water temperature
- Strange noises
- High energy bills
Then a leaking or failing hot water tank could be the issue. Hot water systems have a lifespan of around 8 to 12 years.
If your system is ageing and showing the above signs, it may be past the point where repairs or replacements are cost-effective options.
Leaving a leaking tank running is inefficient, can cause serious water damage to your property and can drive up your bills.
We recommend having your hot water tank inspected annually to ensure you’re getting the most out of your system. Your plumber will be able to tell you if it’s time to say goodbye to the old and in with the new. Or if the system can be repaired.
5. Sediment Build-Up
Perth’s water supply contains minerals that can settle at the bottom of your hot water tank and, over time, can become an issue.
This sediment build-up is a common problem and can affect how your hot water system performs.
As the sediment builds up, it creates a barrier between the heating elements and the water. This makes it harder for the system to heat the water efficiently, often resulting in:
- Inconsistent water temperature.
- Longer heating times.
- Higher energy consumption.
Sediment build-up causing these issues is preventable. Regular maintenance, including flushing the tank, can help remove sediment and keep your system working properly for longer.
While flushing may sound simple, it’s best to have a licensed plumber carry it out to avoid damage and ensure the system is cleaned safely and effectively.
6. Faulty Tempering Valve
If your system appears to be working but you’re only getting cold water at the taps, the issue might be a faulty tempering valve. This valve blends hot and cold water to deliver a safe temperature at the tap.
When it fails, it can let too much cold water through, making it feel like you have no hot water in the house, even when the tank is full and hot. It’s a simple fix for a plumber, but it’s easy to misdiagnose if you don’t know what you’re looking for.
Hot Water in Some Taps But Not Others?
If you’ve got hot water in the kitchen but nothing in the bathroom, or vice versa, the issue is likely localised rather than system-wide.
This often points to a blocked pipe, a faulty mixer tap, or a water flow issue in a specific section of your plumbing.
A tempering valve imbalance or a pressure issue can also cause this kind of uneven hot-water delivery. A plumber can trace the problem to its source and sort it out quickly.
When You Need to Call a Plumber Right Away
Some hot water issues are urgent. Call a licensed plumber immediately if:
- Your circuit breaker keeps tripping after being reset
- You can smell gas near your system
- Your unit is actively leaking
- You’ve had no hot water for more than 24 hours
- Error codes are showing and won’t clear
Hot water systems aren’t something to take risks with. They involve electricity and gas, and in WA, DIY repairs are illegal. If in doubt, call a licensed professional.
Should You Repair or Replace?
Not every fault means your system needs to be replaced. If it’s under 8 years old and this is a first-time issue, a repair is usually best.
But if your system is pushing 10 to 15 years, breaking down regularly, or driving up your energy bills, replacement is often the more cost-effective long-term decision.
The honest answer is that it depends on the system, the fault, and your situation, which is why it’s worth having a professional assess it before you commit to either option.
If you’re unsure, it’s always safer to have a plumber inspect it early before it turns into a bigger issue.
FAQs
Why do I have cold water but no hot water? Usually a faulty heating element, a thermostat issue, or a gas supply problem. These components are responsible for heating the water, so when they fail, only cold water flows through.
How long until hot water comes back? Electric systems take around 1 to 2 hours to recover. Gas systems usually restore hot water within 30 to 60 minutes.
Is no hot water considered an emergency? Yes, especially in colder months or if your household or business relies on it. The sooner it’s assessed, the better.
