Woke up to cold water? Checked the unit and the pilot light is out? Before you pick up the phone, there are a few things you can safely check yourself.

Not everything needs a plumber. But gas work has a hard legal line in NSW, and crossing it isn’t worth the risk. This guide walks you through what you can do at home, what to look for, and exactly when to stop and call a licensed gas fitter.

The Safety Check

Before you touch anything on the unit, do these three checks first. They take less than a minute and they’re non-negotiable.

1. Smell the air around the unit.

Get close to the hot water system and take a slow breath through your nose. Natural gas is odourless on its own, but gas suppliers add a chemical called mercaptan that smells like rotten eggs. If you pick up that smell — even faintly — stop right there. Do not try to relight anything. Turn off the gas at the meter if you can do so safely, get everyone out of the house, leave doors and windows open on your way out, and call the gas emergency line or 000 from outside.

This is not being dramatic. Gas leaks are rare, but they’re serious. Check first, every time.

2. Look at the area around the unit.

Is there water pooling around the base? Scorch marks? Visible damage to the flue pipe or casing? Anything that looks wrong — corrosion eating through metal, panels hanging off, burn marks — means the unit needs professional eyes. Don’t investigate further yourself.

3. Check for good ventilation.

Gas hot water systems need airflow around them to operate safely. If something has been stacked against the unit — boxes, garden furniture, a tarp thrown over it — clear it away before you go any further. Blocked ventilation can cause incomplete combustion, which produces carbon monoxide. You can’t smell or see carbon monoxide, so keeping the area clear is one of the simplest safety things you can do.

Passed all three? Good. Now you can start checking the straightforward stuff.

Is the Gas Actually On?

Sounds obvious, but this catches people more often than you’d think.

Your gas hot water system has its own isolation valve — a small tap or lever on the gas pipe running to the unit. It’s usually within a metre of the system. Check that it’s in the open position. On most valves, the handle runs parallel to the pipe when it’s open and perpendicular (across the pipe) when it’s closed.

If you’re on mains gas, also check the gas meter. Some meters have a main shut-off valve that might have been turned off — maybe after other work was done on the property, or by a previous tenant.

If you’re on LPG bottles, check whether the bottle is empty. Give it a shake or lift it slightly. If it feels light, switch to your reserve bottle (most LPG setups have two) and open the valve. If both bottles feel empty, you’ve found your problem — call your LPG supplier for a refill, not a plumber.

This check alone solves about one in ten “my pilot light won’t work” calls we get across Sydney. Five seconds of looking at a valve can save you a callout.

Read the Relighting Instructions on Your Unit

Every gas hot water system sold in Australia has relighting instructions printed on the unit itself — usually on a label on the front panel or on the inside of the access door. Read them. They’re specific to your brand and model, and the steps do vary.

Here’s the general process, but always follow your unit’s instructions over these:

1. Turn the gas control knob to OFF. Wait a full five minutes. This lets any residual gas in the burner compartment dissipate. Do not skip this step.
2. Turn the knob to the PILOT position.
3. Press and hold the knob down (some units have a separate pilot button — check your label).
4. While holding the knob, press the piezo igniter button. You should hear a click and see a small flame appear through the viewing window. If your unit doesn’t have an igniter, use a long-reach barbecue lighter at the pilot opening.
5. Keep holding the knob down for 30 to 60 seconds. This heats the thermocouple — the safety sensor that tells the gas valve “the pilot is lit, it’s safe to keep the gas flowing.”
6. Release the knob slowly. If the pilot stays lit, turn the knob to ON and set your preferred temperature.

That’s it. If it worked, you’re done. Run a hot tap for a few minutes and check that the water heats up. If it does, your pilot light just needed relighting — no plumber required.

If the pilot won’t stay lit after two or three attempts, stop. Don’t keep trying. Something inside the unit has failed, and from this point forward, it’s gas fitter territory.

Look at the Pilot Flame (If It Lit)

If you got the pilot to light — even briefly — take a look at the flame through the viewing window. This tells you a lot about what’s going on.

Healthy pilot flame: Small, steady, mostly blue with a small yellow tip. The flame should be touching the thermocouple (the thin metal rod near it). If this is what you see, your system is operating normally.

Weak or flickering flame: If the flame is small, lazy, or flickering, the pilot burner orifice might be partially blocked with dust or debris. This is a common issue in Sydney homes, particularly in suburbs with a lot of tree cover — Wahroonga, Turramurra, Beecroft — where spiders and insects get into the burner compartment. Cleaning the orifice is a gas fitter job.

Yellow or orange flame: If the pilot flame is entirely yellow or orange instead of blue, the gas isn’t burning cleanly. This is called incomplete combustion, and it means the system is potentially producing carbon monoxide. Do not ignore this. Turn the unit off at the gas isolation valve and call a licensed gas fitter.

Flame lights then dies immediately when you release the knob: The thermocouple is almost certainly the problem. It’s worn out and can’t generate the electrical signal needed to keep the gas valve open. This is the single most common pilot light fault we see, and it’s a straightforward repair for a gas fitter.

Look Around the Unit’s Location

Where your hot water system sits matters. A quick look at the surroundings can tell you why the pilot went out in the first place.

Wind exposure. Is the unit in a spot that cops a lot of wind? Side passages between houses, under eaves that funnel gusts, near open car ports — these are all common pilot-killer locations. If you’re in a suburb that gets regular wind off the harbour or the coast — think Manly, Cronulla, Maroubra, or anywhere along the Northern Beaches — wind blowout is a frequent culprit. A draught guard fitted around the burner compartment fixes this.

Debris in or around the unit. Leaves, cobwebs, dirt buildup around the base or inside the access panel. These restrict airflow and can partially block the burner. If you can see obvious debris around the outside of the unit, gently clear it away. Don’t reach inside the burner compartment — leave that to the gas fitter.

Flue condition. The flue is the metal pipe or cowl on top of the unit that vents combustion gases. If it’s dented, rusted through, disconnected, or has a bird nest sitting in it, that’s affecting how the system operates. You can look — just don’t try to repair it yourself. Flue work falls under gas installation standards.

Other Gas Appliances in the House

This is a quick one. Turn on your gas cooktop. Does it light? Is the flame strong and blue, or is it weak and yellow?

If all your gas appliances are underperforming — weak cooktop flame, gas heater barely warming up, hot water pilot won’t stay lit — the issue might not be the hot water system at all. It could be a gas supply or pressure problem further up the line. A gas fitter can test line pressure in a few minutes with a manometer and work out where the issue is.

If the cooktop works perfectly and the hot water system is the only problem, the fault is in the unit itself.

Where the Line Is: What You Can Do vs. What Needs a Gas Fitter

This is the part that matters most.

What you can safely do yourself:

• Check for gas smell (and evacuate if you find one)
• Check the gas isolation valve is open
• Check LPG bottles aren’t empty
• Clear debris from around the outside of the unit
• Relight the pilot following the manufacturer’s instructions on the unit
• Look at the pilot flame colour through the viewing window
• Check other gas appliances to see if the issue is system-wide

What requires a licensed gas fitter — no exceptions:

• Replacing a thermocouple
• Cleaning or replacing the pilot burner assembly
• Adjusting gas pressure
• Repairing or replacing the gas valve
• Any work on the flue
• Any work on gas lines or fittings
• Any internal component repair or replacement
• Full system replacement

In NSW, all gas work beyond relighting a pilot must be performed by a tradesperson holding a Gas Work Licence issued by NSW Fair Trading. The work must comply with AS/NZS 5601 (the Australian standard for gas installations), and a compliance certificate must be issued when the job is complete.

This isn’t red tape for its own sake. Gas work done incorrectly can cause gas leaks, carbon monoxide poisoning, fire, or explosion. It voids your home insurance. It voids the manufacturer’s warranty. And it’s illegal. The compliance certificate protects you — it’s proof the work was done safely, done to standard, and done by someone qualified to do it.

If a tradesperson does gas work and doesn’t offer a compliance certificate, that’s a red flag. Don’t use them again.

What Does It Cost to Fix?

Honestly, it depends on what’s wrong. Different brands use different parts. Access to the unit affects labour time. If the system is old and three things are failing at once, the conversation shifts from repair to replacement.

We’re not going to guess at a number here because it would be meaningless without knowing your specific situation. What we will do is tell you straight — over the phone or on-site — what the issue is, what it’ll cost, and whether the repair makes sense or whether you’re better off putting the money toward a new system.

Call us for a straight answer. No runaround.

Frequently Asked Questions

Is it dangerous if my gas hot water pilot light goes out?

Not immediately. Modern gas hot water systems are designed to shut off the gas supply automatically when the pilot light goes out. The thermocouple — a safety sensor sitting in the pilot flame — cools down when the flame dies. Once it cools, it stops sending the electrical signal that holds the gas valve open, and the valve closes within seconds. Gas doesn’t keep flowing just because the pilot is out. That said, you should always do a smell check around the unit before attempting to relight it. If you detect a rotten egg odour at any point, that’s the mercaptan additive in natural gas warning you of a potential leak. Don’t touch the unit, don’t flick any switches, get everyone out of the house, and call 000 or the gas emergency line from outside. The pilot going out is usually harmless. The smell of gas is never harmless.

Can I relight the pilot light myself or do I need a licensed gas fitter?

You can relight the pilot yourself — this is the one thing on a gas hot water system that homeowners are permitted to do without a licence. Every unit has specific relighting instructions printed on a label on the front panel or inside the access door. Follow those instructions for your model, because the process varies between brands. The general steps are: turn the gas knob to off, wait five minutes for residual gas to clear, turn to pilot, press and hold the knob while clicking the igniter, hold for 30 to 60 seconds, then release slowly. If the pilot stays lit, turn the knob to on and you’re done. If the pilot won’t stay lit after two or three attempts, that’s your signal to stop. Something internal has failed — a worn thermocouple, a faulty gas valve, a blocked pilot orifice — and diagnosing or repairing any of those requires a licensed gas fitter under NSW law.

What should I check before calling a plumber about my pilot light?

Start with a safety check — smell for gas around the unit and look for visible damage, scorch marks, or water pooling at the base. If everything looks and smells normal, check that the gas isolation valve on the pipe leading to the unit is in the open position. If you’re on LPG, check whether the bottles are empty. Then try relighting the pilot following the manufacturer instructions on the unit label. If the pilot lights and stays lit, run a hot tap and confirm the water heats up — you’ve solved it yourself. If the pilot won’t stay lit, look at the flame colour through the viewing window. A yellow or orange flame means incomplete combustion and you should turn the unit off. Also check whether other gas appliances in the house are working normally — if everything is underperforming, the issue might be gas supply pressure rather than the hot water unit itself. These checks take five minutes and help your plumber diagnose faster if you do need to call.

How do I know if my thermocouple is the problem?

The classic sign is that the pilot flame lights when you hold the knob down, but goes out within a few seconds of releasing it. The thermocouple is a thin metal rod positioned directly in the pilot flame. When heated, it generates a tiny electrical signal — millivolts — that tells the gas valve to stay open. Over time, the thermocouple tip degrades from constant heat exposure and produces a weaker signal. Eventually it can’t hold the gas valve open on its own, so the moment you release the knob and remove the manual override, the valve closes and the pilot dies. Thermocouples are wear items with a typical lifespan of five to ten years depending on usage and the system. Replacing one is a straightforward job for a licensed gas fitter and is one of the most common gas hot water repairs we do across Sydney. If your unit is otherwise in good condition, a thermocouple replacement is well worth doing.

Why does my pilot light keep going out in the same spot every winter?

Wind is almost certainly the cause. During Sydney’s cooler months, wind patterns shift and certain spots around a house become natural wind tunnels — side passages between buildings, areas under eaves, spots near open carports or garages. If your hot water unit sits in one of these locations, gusts push air into the burner compartment and blow the pilot flame out. This is especially common in exposed suburbs along the coast and harbour — Manly, Dee Why, Cronulla, Coogee — and in elevated suburbs that catch cross-winds like Castle Hill or Hornsby Heights. The fix is a draught guard or wind shield fitted around the burner compartment. It’s a simple addition your gas fitter can install during a service call. If the pilot goes out once after a big storm, that’s weather. If it goes out repeatedly through winter, get the wind protection sorted and you won’t have the problem again.

Do I need a compliance certificate for gas hot water repairs in Sydney?

Yes. Under NSW gas safety regulations, a compliance certificate is legally required after any gas work is completed. This covers repairs, replacements, new installations, and any modification to gas lines or gas appliances. The certificate confirms three things: the work was done by someone holding a Gas Work Licence from NSW Fair Trading, it meets the requirements of AS/NZS 5601 (the Australian standard for gas installations), and the system is safe to operate. Your gas fitter should hand you this certificate when the job is finished — you should never have to chase them for it. Keep it with your home records. You’ll need it if you ever make an insurance claim, sell the property, or need warranty work on the appliance. If a tradesperson completes gas work and doesn’t provide a compliance certificate, that’s a serious red flag — it may mean they’re not properly licensed, and the work may not meet safety standards.

Need a Hand? Call CS Plumbing

If you’ve run through the checks above and the pilot still won’t stay lit — or you’ve spotted something that doesn’t look right — give us a call. We’re licensed plumbers and gas fitters servicing Sydney, and we’ll tell you exactly what’s going on, what it’ll cost, and whether the repair makes sense.

No guesswork, no pressure, no surprises.

Call CS Plumbing — 0416 101 022 — or visit csplumbingservices.com.au