How to identify a gas leak: a homeowner’s guide
If you suspect a gas leak, your first move is to get out. Leave the building immediately if the smell is strong or you feel unwell, and call 000 if there is any fire, explosion, or you cannot stop the smell. From a safe location outside, turn off the gas at the meter only if you can do so without entering the affected area, open doors and windows to ventilate, and contact your gas distributor or a licensed gas fitter. Reactive Plumbing & Electrical is a licensed local option for homeowners who need professional detection and repair.
- Leave immediately if the smell is strong or you feel dizzy, nauseous, or unwell
- Call 000 for fire, explosion, or any leak you cannot stop
- Turn off appliances and pilot lights if safe to do so
- Open doors and windows to ventilate before you leave
- Shut off the gas supply at the meter only if you can reach it safely from outside
- From outside, call your gas distributor (the number is on your gas bill) or a licensed gas fitter
Never attempt to repair a gas leak yourself. Repairs must be carried out by a licensed gas fitter — no exceptions.
Table of Contents
- How do you recognise the signs of a gas leak?
- What should you do — and not do — right now?
- How do natural gas and LPG behave differently at home?
- What does flame colour tell you about combustion safety?
- When should you call 000, your distributor, or a gas fitter?
- What happens after you call a professional?
- How do licensed gas fitters find and fix leaks?
- How do you reduce the risk of future gas leaks?
- Key takeaways
- The part most homeowners get wrong
- Reactive Plumbing & Electrical: licensed gas leak detection, available now
- Useful sources
- FAQ
How do you recognise the signs of a gas leak?
The most obvious sign is a rotten-egg or sulphur smell. That odour comes from mercaptan, a chemical added to natural gas and LPG specifically so people can detect it. But some leaks are faint or odourless — particularly underground leaks, where soil can filter out the mercaptan before it reaches you. Never assume no smell means no leak.
Sounds and appliance behaviour to watch for:
- A hissing or whistling noise near pipes, fittings, or appliances
- Pilot lights that frequently go out or won’t stay lit
- A flame that burns yellow or orange instead of blue
- Soot or scorch marks around burners or appliance vents
Non-appliance warning signs:
- Unexplained spikes in your gas bill without any change in usage
- A discrete patch of dead or dying lawn with no obvious cause
- Bubbles rising in puddles or standing water near gas lines
- Physical symptoms in the household: headaches, dizziness, sore eyes, or throat irritation
Pro Tip: If you notice a dead patch of grass over where your gas line runs, treat it as a gas leak warning sign until a licensed gas fitter rules it out. Underground leaks often show up in the garden before they show up inside.
What should you do — and not do — right now?
Steps to take in order
- Turn off all gas appliances and make sure pilot lights are extinguished
- Open every door and window to ventilate the space
- Evacuate everyone from the building, including pets
- Turn off the gas supply at the meter if you can reach it safely without re-entering the affected area
- Move well away from the building before making any calls
- Call 000 if there is fire, explosion, or an uncontrolled leak; otherwise call your gas distributor or a licensed gas fitter
What not to do
- Do not use any electrical switches, including light switches or power points
- Do not use a mobile phone, landline, or any device that could create a spark while inside
- Do not smoke, light a match, or use a lighter anywhere near the property
- Do not attempt to locate the leak using a naked flame
- Do not try to repair any fitting, pipe, or appliance yourself
- Do not re-enter the building until a licensed professional has declared it safe
The distinction between who to call matters. Call 000 for immediate danger. Call your gas distributor for supply isolation when there is no fire or explosion. Book a licensed gas fitter for any repair work between the meter outlet and your appliances.
How do natural gas and LPG behave differently at home?
Understanding which gas you have changes where you look and how you ventilate. Natural gas (methane) is lighter than air and tends to rise, dispersing toward the ceiling and roof spaces. LPG (propane) is heavier than air and pools in low-lying areas — drains, basements, floor cavities, and confined spaces at ground level.
| Property | Natural gas (methane) | LPG (propane) |
|---|---|---|
| Weight relative to air | Lighter — rises | Heavier — sinks |
| Where it accumulates | Ceiling, roof spaces | Basements, drains, floor level |
| Ventilation priority | Open high windows and roof vents | Ventilate low points and confined spaces |
| Detection focus | Check high points and upper fittings | Check low points, drains, and floor cavities |
| Emergency contact | Gas distributor (on your bill) | LPG supplier (name on cylinder) |
For LPG users, extra care is needed to ventilate basements and confined spaces before re-entering, because pockets of heavier-than-air gas can linger long after the source is isolated. Natural gas tends to disperse more quickly once ventilation is opened, but accumulation in roof spaces is still a real risk in poorly ventilated homes.
What does flame colour tell you about combustion safety?
A healthy gas burner produces a steady blue flame. That colour tells you the gas is burning completely and efficiently. A persistent yellow or orange flame signals incomplete combustion, which can produce carbon monoxide — a colourless, odourless gas that is genuinely dangerous at elevated concentrations.
Appliance warning signs to record and report:
- A flame that burns yellow, orange, or red rather than blue
- A flame that lifts off the burner or flickers excessively
- Pilot lights that go out repeatedly without explanation
- Soot deposits or black marks around burner heads or appliance vents
- An unusual smell when an appliance is running
If you see a persistent yellow flame, turn the appliance off and do not use it again until a licensed gas fitter has inspected it. When you call, tell the technician the appliance type, the flame colour you observed, and roughly when you first noticed it. That information helps them diagnose the root cause faster and reduces time on site.
Carbon monoxide cannot be seen or smelled. If multiple people in the household develop headaches or feel unwell at the same time, particularly when a gas appliance is running, treat it as a potential carbon monoxide issue and evacuate immediately.
When should you call 000, your distributor, or a gas fitter?
Getting the call sequence right saves time and keeps everyone safer.
- Call 000 if there is fire, explosion, anyone is unwell, or the leak is uncontrolled and you cannot stop it
- Call your gas distributor (number on your gas bill) if there is no immediate danger but you cannot locate or stop the leak — they can isolate the supply at the main
- Book a licensed gas fitter for any repair work on pipework or appliances between the meter outlet and your home
Gas distributors may attend to make the situation safe by shutting off supply, but they will not repair appliances or internal pipework. That work legally requires a licensed gas fitter. Have the technician’s licence number ready before they start work.
- For NSW emergencies: Energy Safe Victoria guidance applies in Victoria; each state has an equivalent regulator
- Australian Gas Networks emergency line: 1800 GAS LEAK (1800 427 532) for east coast customers
- ATCO Faults and Emergencies: 13 13 52 for west coast customers
What happens after you call a professional?
Expect the job to follow a clear sequence: safety triage first, then diagnosis, then repair and certification.
- Safety triage: The distributor or first responder isolates supply and confirms the area is safe to enter
- Diagnostic checks: The gas fitter conducts pressure tests and uses electronic gas detectors or a soap solution on joints to pinpoint the leak location
- Isolation and repair: Fittings are tightened or replaced, pipe sections are repaired or replaced, and underground lines are excavated where necessary
- Pressure test and certification: A final pressure test confirms the repair, and the fitter issues a certificate of gasfitting work
Cost varies depending on leak location, access difficulty, parts required, and whether an emergency call-out rate applies. Underground leaks or those inside wall cavities take longer and cost more than an accessible fitting repair. Always ask upfront for the call-out rate and an estimate once the leak is located.
Pro Tip: Ask every gas fitter for their licence number before work begins, and request a certificate of gasfitting work on completion. That certificate is your proof of compliance and may be required for insurance claims or future property sales.
How do licensed gas fitters find and fix leaks?
Professional detection goes well beyond sniffing around. A licensed gas fitter uses a combination of methods to locate a leak precisely before any repair begins. You can read more about the tools used to check for gas leaks on the Reactive Plumbing & Electrical website.
- Electronic combustible gas detector: A handheld device that detects gas concentrations in the air, used to sweep rooms, fittings, and pipe runs
- Pressure testing: The gas system is isolated and pressurised; a drop in pressure confirms a leak is present and helps narrow its location
- Soapy water on joints: Applied to fittings and connections — bubbles form at the leak point, a reliable low-tech method for accessible joints
- Tracer gas: An inert tracer gas is introduced into the pipe; a detector traces where it escapes, useful for underground or concealed lines
- Appliance and regulator inspection: Regulators, flexible hoses, and appliance connections are checked for wear, corrosion, or damage
Repair methods depend on what the inspection finds:
- Tighten or replace fittings and flexible hose connections
- Replace sections of damaged or corroded pipe
- Repair or replace faulty regulators or appliance components
- Excavate and repair underground service lines where required
Only a licensed gas fitter may carry out these repairs under Australian law. Once complete, a pressure test and visual inspection verify the fix, and the fitter issues the required compliance paperwork. In some cases, the gas distributor will conduct a follow-up check before restoring supply.
How do you reduce the risk of future gas leaks?
Prevention comes down to regular checks and protecting your gas infrastructure from accidental damage.
- Quarterly: Walk around and visually check external gas piping, flexible hoses, and appliance connections for signs of corrosion, damage, or movement
- Annually: Book a service with a licensed gas fitter to inspect all gas appliances, check burner performance, and test system pressure
- After renovations or groundworks: Arrange an immediate inspection — DIY excavation and gardening are common causes of underground pipe damage
- Cylinder storage: Keep LPG cylinders upright, outdoors, and away from ignition sources; check the supplier’s emergency contact details are visible on the cylinder
- Flue maintenance: Keep appliance flues and vents clear of debris, bird nests, and vegetation to prevent combustion gases from backing up indoors
After any gas event, improving your home’s indoor air quality is worth considering — ventilation plays a real role in recovery. Keep a folder with service records, certificates of gasfitting work, and appliance manuals. That documentation supports warranty claims, insurance, and compliance checks.
Pro Tip: Call before you dig. Dial 1100 (Dial Before You Dig) to get underground service locations marked before any excavation, even shallow gardening near known gas lines.
Key takeaways
Identifying a gas leak quickly and responding correctly — evacuate, ventilate, isolate, and call a licensed professional — is the single most important thing a homeowner can do to stay safe.
| Point | Details |
|---|---|
| Smell is the first alert | A rotten-egg odour from mercaptan is the primary warning sign, but underground leaks can be odourless. |
| Blue flame means safe combustion | A persistent yellow or orange flame signals incomplete combustion and needs immediate inspection. |
| Know who to call | Call 000 for danger; your gas distributor for supply isolation; a licensed gas fitter for repairs. |
| Distributors don’t do repairs | Gas distributors isolate supply only; all appliance and pipework repairs require a licensed gas fitter. |
| Reactive Plumbing & Electrical | A licensed local provider offering 24/7 gas leak detection and repair, with a certificate of gasfitting work on completion. |
The part most homeowners get wrong
There is a gap between knowing a gas leak is dangerous and actually acting fast enough. Most homeowners who call us describe a delay — they smelled something faint, assumed it was the neighbour’s barbecue, and waited to see if it got worse. That hesitation is understandable, but it is also where the risk compounds.
What we see on arrival is usually one of two things: an appliance connection that has worked loose over years of use, or an underground service line nicked during gardening or a small renovation. Neither is dramatic. Both are genuinely hazardous if left unaddressed.
The licensing and certification requirements under AS/NZS 5601 exist precisely because gas work is unforgiving when it goes wrong. A certificate of gasfitting work is not bureaucratic paperwork — it is your confirmation that the repair was done correctly and that the system was pressure-tested before gas was restored. If a tradesperson cannot or will not provide one, that is a serious red flag.
My advice: photograph the appliance, note the date and what you observed, and keep any distributor attendance records. That evidence helps the gas fitter diagnose faster and protects you if an insurance question arises later.
Reactive Plumbing & Electrical: licensed gas leak detection, available now
Gas leaks don’t wait for business hours, and neither do we. Reactive Plumbing & Electrical provides 24/7 emergency gas leak detection and repair for homeowners across Sydney, Newcastle, Wollongong, Brisbane, Ipswich, and the Gold Coast. Every job is carried out by a licensed gas fitter, and we issue a certificate of gasfitting work on completion so you have documented proof the repair meets Australian safety standards.
When you call, have your appliance details and any symptoms you observed ready — flame colour, smell intensity, sounds, and whether the gas distributor has already attended. That information lets us triage faster and arrive prepared. Whether it is an urgent call-out or a scheduled annual service, our team is equipped to locate the leak, carry out the repair, and restore your gas supply safely. To book or get advice, visit reactiveplumbingandelectrical.com.au or call us directly.
Useful sources
These are the primary Australian sources that underpin the safety guidance in this article. Bookmark your gas distributor’s emergency number and keep appliance manuals accessible.
- Energy Safe Victoria: Victoria’s gas safety regulator; covers emergency procedures, installer obligations, and reporting requirements for both natural gas and LPG
- NSW Government — Gas Safety: Consumer rights, licensing requirements, and when to call 000 versus a licensed gas fitter
- SA Government — Gas Leaks: Step-by-step procedural guidance on ventilation, meter isolation, and who to contact
- Queensland Government — Gas Safety: Covers natural gas and LPG behaviour, storage, and safe use at home
- Australian Gas Networks: East coast gas distributor emergency guidance and the 1800 GAS LEAK line
- AS/NZS 5601: The Australian and New Zealand standard for gas installations; governs what licensed gas fitters must do and certify — available through Standards Australia
Keep your gas distributor’s emergency number saved in your phone. It is printed on every gas bill.
FAQ
What does a gas leak smell like?
Natural gas and LPG are odourless on their own, but suppliers add mercaptan, which smells like rotten eggs or sulphur. If you notice that smell indoors, treat it as a gas leak until a licensed professional confirms otherwise.
Can a gas leak have no smell at all?
Yes. Underground leaks can filter out the mercaptan odour through soil, making them faint or completely odourless. Look for dead patches of lawn, bubbles in standing water, or unexplained rises in your gas bill as alternative warning signs.
How do I safely check for a gas leak at home?
You can apply a soapy water solution to accessible pipe joints and fittings — bubbles indicate escaping gas. For anything beyond a visible joint, use a handheld gas detector or call a licensed gas fitter; never use a naked flame to test for leaks.
Who do I call for a gas leak in Australia?
Call 000 for fire, explosion, or any uncontrolled leak. For supply isolation without immediate danger, call your gas distributor (the number is on your gas bill). For repairs to pipework or appliances, book a licensed gas fitter such as Reactive Plumbing & Electrical.
What is a certificate of gasfitting work?
It is the compliance document a licensed gas fitter must issue after completing gas repairs or installations in Australia. It confirms the work meets AS/NZS 5601 and that the system was pressure-tested before gas was restored. Always request one on completion.