Quick Answer
If you have no hot water, the most common causes are a tripped circuit breaker, failed heating element, faulty thermostat, or pilot light outage (gas systems). Check the obvious things first — power supply, circuit breaker, gas valve — before calling a plumber. Most hot water system faults can be diagnosed in 10 minutes and many are fixed without a call-out. Expect $150–$400 for a plumber’s diagnostic visit and minor repair, or $1,800–$4,500 for a full system replacement.
Waking up to no hot water is one of those home emergencies that feels urgent but is often a quick fix. Melbourne’s cold winters — particularly in the south-east suburbs — mean this issue hits hardest in June and July. This guide walks you through the diagnostic process from easiest to most complex, so you can identify the cause before calling a plumber.
Step 1: Identify Your Hot Water System Type
| System Type | How to Identify | Common Faults |
|---|---|---|
| Electric storage tank | Large cylinder, no gas pipe or flue, power cable connected | Failed element, tripped breaker, failed thermostat |
| Gas storage tank | Large cylinder with gas pipe and flue/exhaust pipe | Pilot light out, gas supply fault, thermocouple failure |
| Gas continuous flow (instantaneous) | Small wall-mounted box, activates only when tap runs | Ignition failure, gas supply fault, error code displayed |
| Heat pump | Large tank with fan unit on top, power cable connected | Compressor fault, refrigerant issue, controller error |
| Solar (with electric/gas boost) | Roof panels plus storage tank | Boost element fault, controller failure, cloudy day depleted tank |
Step 2: Check These First (Before Calling Anyone)
Electric Systems
- Check the circuit breaker. Open your switchboard and look for a tripped breaker labelled “Hot Water”, “HWS”, or “Storage”. Reset it by flicking it off then fully on. If it trips again immediately, there’s a wiring or element fault — call an electrician.
- Check the off-peak timer. Many electric storage systems run on off-peak tariffs (Economy 7 or Controlled Load). If your timer is faulty or has lost settings, the element may not have heated overnight. Call your electricity retailer to check.
- Wait 2–4 hours. If the element was off all night and you’ve just restored power, you need to wait for a full tank to reheat (60–80 litres takes 2–4 hours on a standard 2.4kW element).
Gas Storage Systems
- Check the pilot light. Look through the small window on the burner unit at the base of the tank. If the pilot flame is out, follow the re-lighting instructions on the unit label (usually hold the pilot button while lighting).
- Check the gas supply. Turn on a gas stove burner — if it doesn’t light either, the gas supply to the house is interrupted. Check with your gas retailer or neighbours.
- Check the thermocouple. If the pilot lights but won’t stay lit when you release the button, the thermocouple is likely faulty. This is a plumber’s job — a new thermocouple costs $80–$150 installed.
Continuous Flow (Instantaneous) Gas Systems
- Check the display for error codes. Rinnai, Bosch, Rheem, and Dux all have error code displays. Note the code and search “[brand] error code [number]” for a specific diagnosis.
- Check water flow rate. Continuous flow units need a minimum flow rate (usually 2–3 litres per minute) to activate. A partially closed valve or blocked aerator can prevent activation.
- Check the gas supply as above.
When to Call a Plumber
| Symptom | Likely Cause | Who to Call |
|---|---|---|
| Circuit breaker trips repeatedly | Failed heating element shorting to earth | Electrician or plumber (element replacement) |
| Pilot lights but won’t stay lit | Faulty thermocouple | Licensed plumber — $80–$150 |
| Water discoloured (brown or rusty) | Corroding sacrificial anode or tank | Plumber — anode $200–$400, or replacement if tank old |
| Pressure relief valve dripping constantly | Thermostat overheating water or failing valve | Plumber — urgent; scalding risk |
| Visible leak from tank | Tank failure — irreparable | Plumber — replacement required |
| Unit over 10–12 years old | End of service life approaching | Plumber — consider replacement before failure |
Top 10 Tips for Dealing With No Hot Water
- Check the obvious before calling anyone. Tripped breakers and extinguished pilot lights account for about 30% of “no hot water” call-outs — and both are free fixes.
- Know your system’s age. The manufacture date sticker is usually on the upper side of the tank. Electric storage systems last 8–12 years; gas systems 10–15 years. If yours is near end of life, replacement is often smarter than repair.
- Have a temporary solution ready. Electric kettles, camping showers, or gym memberships can tide you over while waiting for a plumber. Ask your plumber for an ETA before committing to wait-at-home.
- Don’t run all the hot taps to check. If you have a storage system with residual warm water, running multiple taps wastes what little hot water remains. Use sparingly until the system is repaired.
- Check if your insurer covers sudden failures. Some home insurance policies cover sudden appliance breakdown — check before paying for a replacement out-of-pocket.
- Get quotes before agreeing to emergency rates. Emergency plumber rates in Melbourne can be $180–$250/hr on weekends. If the situation isn’t critical, booking a weekday call-out can save $100–$200.
- Ask about VIC government rebates. If you’re replacing an old electric or gas unit, heat pump hot water systems qualify for Victorian Energy Upgrades (VEU) rebates — up to $1,000 off the installed price.
- Check the sacrificial anode every 5 years. This magnesium rod inside the tank corrodes sacrificially to protect the tank lining. When it fails, the tank corrodes rapidly. Most homeowners never replace it.
- Set temperature to 60°C minimum. Australian standards require hot water stored at 60°C to prevent Legionella bacterial growth. If your system delivers water cooler than 60°C at the tap, the thermostat needs adjustment.
- Consider upgrading rather than repairing. A heat pump hot water system costs $2,500–$4,000 installed but uses 60–70% less energy than an electric storage system, cutting annual bills by $400–$800.
Local Melbourne Resources
- Reece Plumbing — hot water system spares, thermocouples, and new units; branches across SE Melbourne
- Bunnings — basic hot water spares and pressure relief valves
- Solar Victoria — check current VEU rebates for heat pump hot water systems
- Victorian Building Authority (VBA) — verify your plumber’s licence
- Rheem Australia — service hotline for Rheem hot water systems: 1300 556 036
Frequently Asked Questions
How long does it take for a hot water system to reheat after losing power?
A standard 125–160 litre electric storage tank takes 2–4 hours to fully reheat from cold using a 2.4kW element. A gas storage system typically reheats faster — 1–2 hours. Continuous flow systems produce hot water immediately as long as gas supply and ignition are working.
Why is my hot water running cold after a few minutes?
This is usually a failing heating element (electric) or a thermostat set too low. For electric storage systems, a single-element unit may be drawing lukewarm water from the top of the tank while the element at the bottom heats more water. For continuous flow gas, it can indicate a flow rate issue or a gas pressure problem.
Can I replace a hot water element myself?
No. Replacing a hot water element involves work on a 240V appliance that is also a pressure vessel. In Victoria this requires a licensed plumber and, where electrical connections are involved, a licensed electrician. DIY element replacement is dangerous and voids the unit’s warranty and your home insurance.
How much does an emergency plumber cost in Melbourne?
Emergency plumber rates in Melbourne typically range from $150–$250 per hour on weekdays and $200–$350 on weekends and public holidays, plus a call-out fee of $80–$150. For a minor repair like a thermocouple replacement, the total bill is usually $200–$400. Get a quote before authorising any work.
