Quick Answer
No hot water in your Melbourne home? The most common causes depend on your system type: gas systems fail due to pilot light outages, gas supply issues, or thermocouple failure; electric systems fail due to tripped circuit breakers, burnt-out elements, or thermostat failure; solar and heat pump systems can lose function due to controller faults or pump failures. Work through the quick checks below before calling a plumber — many hot water problems can be diagnosed in 10 minutes and some are free to fix yourself.
Step 1: Identify Your Hot Water System Type
The troubleshooting path is completely different depending on your system. Check the unit in your garage, laundry, or outside wall:
| System Type | What It Looks Like | How to Identify |
|---|---|---|
| Gas storage | Cylindrical tank, usually 90–315L, with a flue pipe at top | Gas connection pipe at base; pilot light window or igniter button |
| Electric storage | Cylindrical tank, same shape as gas but no flue; red indicator light on element cover | Electrical cable connection; no gas pipe; element access panel on lower section |
| Gas continuous flow (instantaneous) | Small wall-mounted box, no tank, often inside or on external wall | Gas pipe connection; no storage tank; brands include Rinnai, Bosch, Rheem Continuous Flow |
| Solar hot water | Storage tank on roof or in roof cavity plus flat panel or evacuated tube collectors on roof | Solar panels on roof; tank may be elevated (thermosiphon) or at ground level (pumped) |
| Heat pump | Large unit with fan on top, resembles a split system outdoor unit, with a storage cylinder | Fan visible; no gas connection; usually installed outside; brands include Reclaim, Sanden, Rheem |
Step 2: Quick Checks Before Calling Anyone
For All System Types
- Is there a water supply? Turn on a cold tap — if cold water is also off or very low pressure, the issue is the water supply, not the hot water system.
- Has anyone used a large volume recently? After a large family visit, filling a spa bath, or washing several loads with hot water, even a 250L tank can be depleted. Wait 2–3 hours for recovery before concluding the system has failed.
- Is there a system isolating valve closed? Check the cold water inlet valve on the hot water unit itself — it should be fully open (handle in line with the pipe).
For Gas Storage Systems
- Check the pilot light. Open the access panel at the base of the unit and look for a small flame (pilot light). If it’s out, follow the relighting instructions on the label — usually: set to pilot, press and hold igniter button, hold for 30 seconds after flame lights, then turn to desired temperature.
- Check your gas supply. Turn on a gas stove or gas cooktop burner. If it also has no gas, your gas supply has been interrupted — check if a gas isolation valve near the meter has been accidentally closed, or call your gas retailer to report a supply outage.
- Check the temperature setting. The thermostat dial should be set to at least 60°C (marked on the dial). Thermostats can sometimes move if bumped.
For Electric Storage Systems
- Check the switchboard. Electric hot water systems have their own dedicated circuit breaker, often labelled “HWS” or “Hot Water”. Check if it has tripped to the middle position or off. Reset by switching fully off then back to on.
- Check the off-peak timer. Many Melbourne homes have electric hot water on a controlled-load tariff that only heats at night (roughly 10pm–6am). If you’re checking at midday, the system may not have heated yet today — it may recover overnight.
- Check the indicator light. A red indicator light on the element cover plate means the element thermal cut-out has tripped. Press the small red reset button (usually recessed — use a pen) on the element cover. This is caused by overheating, often from a thermostat fault.
For Gas Continuous Flow (Instantaneous) Systems
- Check the controller display. Rinnai, Bosch, and Rheem continuous flow units have digital controllers — error codes display on the screen. Common codes: 11 (no ignition — gas supply issue), 12 (flame failure), 16 (overheating), 65 (water flow too low). Search the code + your model number for specific causes.
- Check gas supply as above.
- Check minimum flow rate. Instantaneous systems don’t activate below a minimum flow rate (typically 2–3 litres per minute). A partly closed tap or a tap washer restriction can prevent activation. Turn the hot tap fully open.
Troubleshooting Table
| Symptom | System Type | Most Likely Cause | DIY Fix? |
|---|---|---|---|
| No hot water at all | Gas storage | Pilot light out; gas supply interrupted | Yes — relight pilot or check gas supply |
| No hot water at all | Electric storage | Circuit breaker tripped; element failed | Partly — reset breaker; element replacement needs licensed electrician |
| No hot water at all | Gas continuous flow | Gas supply issue; error code on controller | Check gas first; error codes may need plumber |
| Water warm but not hot | Any storage | Thermostat set too low; thermostat failed; element partially failed | Adjust thermostat; replacement needs trades |
| Hot water runs out quickly | Electric storage | On off-peak tariff — tank not reheated; second element failed | Check off-peak timer; call electrician if element suspect |
| Discoloured or smelly hot water | Any storage | Anode rod corroded; tank sediment buildup; bacteria (Legionella risk) | No — call licensed plumber to inspect anode and flush tank |
| Water dripping from relief valve (TPRV) | Any storage | TPRV opening due to overheating; TPRV faulty; excessive system pressure | No — turn off system and call plumber immediately |
| Wet ground or puddle under unit | Any storage | Tank corrosion and internal failure — end of system life | No — system replacement required |
When to Call a Licensed Plumber
Under Australian law (AS/NZS 3500 plumbing standard), all work on hot water systems involving gas connections, pressure/temperature relief valves, pipe connections, and electrical elements must be done by a licensed plumber or licensed gas fitter. DIY repair of gas components is illegal in Victoria and dangerous. Call a licensed plumber when:
- Your gas pilot light won’t relight after multiple attempts (thermocouple failure)
- Your TPRV is dripping or discharging
- There is a water puddle under your storage tank (tank failure — urgent)
- The water smells of sulphur or is discoloured
- Your circuit breaker resets but immediately trips again (electrical fault in the element or wiring)
- Your system is more than 10 years old and developing any of the above faults
Emergency plumber call-out in Melbourne (after hours) costs $200–$400 call-out plus parts and labour. Same-day business hours call-out is typically $150–$250 plus labour at $120–$180/hour.
Tips and Gotchas
- The average electric storage hot water system lasts 8–12 years. If yours is more than 10 years old and an element fails, strongly consider replacement rather than repair — a new element costs $150–$300 in labour plus parts, and the tank may fail within 1–2 years anyway.
- Off-peak tariffs are not available on all meters. If your previous owner was on a different tariff, your hot water system may be heating during peak hours without you knowing. Check with your retailer — a switch to controlled load can save $100–$200/year.
- Continuous flow systems need descaling every 5 years in Melbourne’s moderate-hardness water areas. Mineral scale on heat exchangers reduces efficiency and eventually causes failures.
- VIC rebates for heat pump hot water systems are available under the Victorian Energy Upgrades program — up to $1,000 off an eligible heat pump hot water system. Check current availability at energy.vic.gov.au.
- Check anode rods every 5 years. The magnesium anode rod inside storage tanks sacrificially corrodes to protect the tank lining. When it’s fully consumed, the tank corrodes. Most homeowners never check this — it’s why tanks fail prematurely.
Local Resources
- Victorian Building Authority — Find a licensed plumber or gas fitter in Melbourne
- Victorian Energy Upgrades — Rebates for heat pump hot water systems
- Reece Plumbing — Hot water system parts, anode rods, replacement units (SE Melbourne branches)
- Bunnings Warehouse — Plumbing fittings, valves, water quality testing
Frequently Asked Questions
How long does it take for hot water to come back after the pilot light goes out?
After relighting the pilot light on a gas storage system, allow 30–60 minutes for a 160–250L tank to fully reheat. The water will warm gradually from the top of the tank first — you’ll have warm water within 20 minutes and full hot water within 45–90 minutes depending on tank size and gas flow rate.
My hot water is only lukewarm — is the element broken?
Lukewarm water (not cold, just not hot) often means the thermostat is set below 60°C, or that one element in a dual-element system has failed. Single-element systems with a failed element produce no hot water at all. Check the thermostat dial setting first — it should be at 60°C. If set correctly, the thermostat or lower element may have failed and needs an electrician to test.
Is it safe to shower if my hot water smells like rotten eggs?
A sulphur or rotten egg smell from hot water (not cold) indicates bacterial activity in the storage tank, typically from Legionella or sulfate-reducing bacteria. Do not use hot water for drinking or cooking, and avoid inhaling steam from showers until the system has been inspected by a licensed plumber. The tank may need to be flushed, disinfected, and set to maintain 60°C minimum temperature.
Should I repair or replace my hot water system?
If your system is under 8 years old, repair usually makes sense. If it is 10+ years old and an expensive component (element, thermostat, gas valve) has failed, replacement is often better value — particularly with current Victorian rebates making heat pump systems very cost-competitive. A plumber can advise on age and condition after inspection.
