No hot water? Work out why before you call a plumber
A cold shower on a winter morning is not the time to be researching hot water systems. Here is the short version: two checks take about ninety seconds, cost nothing, and solve a decent proportion of the calls we get.
Start here: the two free checks
Before anything else, work out which type of system you have. If it is a tank with an electrical connection, it is electric storage. If it has a flue and a small access panel at the base, it is gas. If it looks like an air conditioner bolted to a tank, it is a heat pump.
- 1Electric: check the switchboardLook for a tripped circuit breaker, often labelled "hot water" or "HWS". If one has tripped, reset it and give the system a few hours. If it trips again straight away, stop — that is a fault in the element or wiring and it needs a licensed tradesperson, not a second reset.
- 2Gas: check the pilot lightMost gas storage systems have a viewing window or an access panel at the base. If the pilot is out, relighting instructions are usually printed on the unit itself. If it relights and stays lit, you are done. If it goes out again, it is very likely the thermocouple.
- 3Heat pump: check power and airflowConfirm it has power at the switchboard, and check the unit is not obstructed or iced over. Heat pumps need clear airflow to work, and something stacked against the unit is a surprisingly common cause.
If you can smell gas, stop
Do not touch any electrical switch, including a light switch. Turn the gas off at the meter, open doors and windows, get everyone outside, and call from outside the building. Do not go looking for the leak yourself.
What the symptom is probably telling you
If the free checks did not solve it, the pattern of the fault usually narrows it down quite a bit before anyone opens the unit.
| What you are seeing | Likely cause | Repair or replace? |
|---|---|---|
| No hot water at all, electric system | Tripped breaker, failed element, or failed thermostat | Usually repair |
| No hot water at all, gas system | Pilot light out, failed thermocouple, or gas valve fault | Usually repair |
| Lukewarm water only | One of two elements failed, or a worn tempering valve | Repair |
| Hot then cold within minutes | Tank not reheating, or undersized for the household | Repair or resize |
| Water discoloured or smells | Depleted sacrificial anode, tank corroding internally | Often replace |
| Water pooling under the unit | Tank body has failed, or a fitting is leaking | Depends — see below |
The one that is not actually a fault
A significant number of the “my hot water keeps running out” calls we take are not faults at all. If your system is on a controlled load tariff — often called off-peak — the element only runs overnight when electricity is cheapest. Draw the tank down during the day and it will not reheat until the early hours.
That works fine for the household the system was sized for. It stops working when the household grows, or when a couple of teenagers start taking long showers. Nothing is broken; the system is doing exactly what it was set up to do.
The options are a bigger tank, moving to a continuous or boosted tariff, or changing system type. We have written that one up separately, because the answer depends a lot on your household.
Water pooling under the unit
This is the one worth acting on quickly, because the answer splits sharply. If water is coming from a fitting, a valve or the drain line, it is generally repairable. If it is weeping from the body of the tank itself, the tank has corroded through and no repair will fix it — that is a replacement.
There is also a third possibility that is completely normal, which is discharge from the TPR valve during a heating cycle. Telling the three apart is straightforward once you know what to look for.
Two things not to do
Do not turn the thermostat down. Stored water is kept above 60°C deliberately, to control Legionella. Lowering it is a health risk, not an energy saving. If your taps run too hot, the correct fix is a tempering valve, which limits the temperature at the outlet while keeping storage safe.
Do not cap or plug a dripping relief valve. It is a safety device. Blocking it turns a leak into a pressure vessel problem.
When to call, and what to have ready
Call once the free checks are done and it has not come back. It helps enormously if you can tell us four things on the phone: the system type, roughly how old it is, the brand if you can see it, and what exactly is happening — no hot water at all, lukewarm, or running out faster than it used to. That is usually enough for us to arrive with the right part on the van rather than making two trips.
Most Illawarra homes still run electric storage, which typically lasts eight to twelve years. Gas storage runs ten to fifteen. If yours is beyond that and something significant has failed, we will tell you honestly rather than quoting a repair that buys you six months. More on expected lifespans and what shortens them, or see our hot water repair service.
Questions we get asked
Why has my hot water stopped working suddenly?
On an electric system, the most common causes are a tripped circuit breaker at the switchboard, a failed heating element or a failed thermostat. On a gas system, the usual culprits are the pilot light going out, a failed thermocouple or a gas valve fault. On a heat pump, check that it has power and that the unit is not iced up or obstructed. The switchboard and the pilot light are both worth checking yourself before calling anyone.
My hot water only works in the morning and runs out by evening.
That usually means the system is on a controlled load, sometimes called off-peak, tariff. The element only heats overnight, so once the tank is drawn down during the day it does not reheat until the small hours. It is not a fault. The fix is either a larger tank, a continuous or boosted tariff, or switching to a continuous flow or heat pump system.
Is it safe to relight my own gas pilot light?
Most gas storage systems have relighting instructions printed on the unit and are designed for the owner to follow them. If it lights and stays lit, you have solved it. If it will not stay lit, that is usually the thermocouple and it needs a licensed gas fitter. If you can smell gas at any point, stop, do not touch any electrical switch, turn the gas off at the meter, ventilate the area and call.
How quickly can you get to a no-hot-water call?
For most of the Illawarra we can usually be there the same day, and we are 24/7 for emergencies. From our Kiama base, Kiama Downs, Minnamurra, Jamberoo and Gerringong are typically the fastest, with Wollongong and Berry a little further out.
Should I just replace it rather than repair it?
Depends on age and what has failed. A component fault on a system under about eight years old for electric or ten for gas is usually worth repairing. If the tank itself is leaking from the body, or the repair would cost more than about half a replacement, replacing is the better buy. If you are replacing, it is worth knowing that a heat pump attracts NSW and federal incentives that a like-for-like electric swap does not.
Need it looked at?
We do same-day hot water repairs across Wollongong, Kiama, Shellharbour and down through Gerringong and Berry. Licensed plumber and gas fitter, 24/7 for emergencies.