Natural gas is odourless in its natural state. The distinctive smell most people associate with a gas leak in West Melbourne is actually added deliberately. Gas suppliers inject a compound called mercaptan (also known as methanethiol) into the gas supply specifically so that leaks can be detected by smell. Without it, a gas leak could fill an entire room before anyone knew it was there. If you know what to look for and what to do, you are in a far better position to keep your household safe.
What Does a Gas Leak Smell Like?
The smell is most often described as rotten eggs, sulphur, or a strong, sour chemical odour. It is unpleasant and distinctive. Mercaptan is added at very low concentrations because it is detectable by the human nose at parts per billion. Even a very faint trace of this smell indoors should be taken seriously and investigated immediately.
How natural gas and LPG behave differently
- Natural gas is lighter than air and rises toward the ceiling, dispersing upward and outward.
- LPG (liquefied petroleum gas) is heavier than air and sinks to floor level, accumulating inside cabinets and in poorly ventilated spaces without being immediately obvious.
Both gases have mercaptan added, and both are flammable. Neither should be ignored, regardless of concentration. Some people compare the smell to a struck match or decaying vegetation. Any of these odours near a gas appliance or pipe warrants immediate action.
Common Sources of Gas Leaks
Understanding where gas leaks typically originate helps you know where to pay attention during routine checks. In residential properties across Melbourne’s western suburbs, the most common sources include:
The five most common leak points
- Ageing or corroded gas pipes: Metal gas pipes can corrode over time, particularly in older properties or in areas where soil movement is common. Hairline cracks and pinhole leaks develop gradually and may not produce an obvious smell until the leak has grown.
- Faulty appliance connections: Flexible gas connectors linking cooktops, ovens, and gas heaters to the supply line can degrade, crack, or work themselves loose over years of use. These connectors have a finite service life and should be inspected periodically.
- Damaged or improperly installed fittings: Any fitting, valve, or junction in a gas line is a potential leak point if it was not installed correctly or has been disturbed during renovations or maintenance work.
- Hot water system connections: Gas hot water systems work under constant load and the connections at the gas inlet are a common site for minor leaks, particularly on older units.
- Gas meters: The meter itself and the pipework around it at the property boundary can develop leaks, particularly if the meter is old or the ground around it has shifted.
Other Signs of a Gas Leak Beyond the Smell
Not every gas leak produces a smell strong enough to notice immediately, particularly if the leak is small, outdoors, or in a well-ventilated area. Watch for these additional warning signs:
Warning signs to look and listen for
- A hissing or whistling sound near a gas line, appliance, or meter — a sign of gas escaping under pressure. Treat this as urgent.
- Dead or discoloured vegetation over underground gas lines — escaping gas displaces oxygen in the soil, causing plants to die in unusual patterns directly above the pipe.
- Bubbling in standing water near underground pipework — gas may be escaping into the soil and surfacing through puddles or rainwater.
- Higher than expected gas bills without a change in usage — a common indicator of a slow, ongoing leak that is wasting gas continuously.
- Pilot lights that go out repeatedly or flames burning orange or yellow instead of a clean blue — this can point to a gas supply problem or appliance fault.
- Symptoms of carbon monoxide exposure — headaches, dizziness, nausea, or fatigue that improve when you leave the house. Incomplete combustion from a faulty gas appliance produces carbon monoxide even when the appliance appears to be working.
What to Do if You Smell Gas
Act quickly. Do not try to locate the leak yourself and do not assume the smell will pass. Follow these steps in order:
Immediate action steps
- Do not turn any electrical switches on or off, including lights, fans, or appliances. Electrical sparks can ignite gas.
- Do not use a mobile phone inside the property. Step outside before making any calls.
- Do not light matches, candles, or cigarettes. Do not use any open flames or heat sources.
- Leave the property immediately, leaving doors open as you go to allow ventilation. Do not stop to collect belongings.
- Turn off the gas at the meter if it is safe and easily accessible without going back inside. The meter is usually at the front boundary of the property.
- Call your gas network operator’s emergency line. In Victoria: 132 771 for Australian Gas Networks (covers much of Melbourne’s west including Melton) or 13 29 52 for Multinet Gas. If there is immediate danger, call 000.
- Do not re-enter the property until it has been declared safe by the gas company or emergency services.
- Once the immediate situation is resolved, call a licensed gas plumber Melton to inspect all appliances and pipework.
After the Emergency: What Happens Next
After a gas emergency, the network operator or emergency services will attend and make the situation safe, confirming the leak, isolating the gas supply, and ventilating the property. They will not repair the cause of the leak. That is the job of a licensed gas fitter.
What a gasfitter must do before gas is restored
- Pressure test the entire gas system to confirm there are no remaining leaks anywhere on the property.
- Visual inspection of all exposed pipework and fittings to identify the source and extent of the damage.
- Appliance check. Every gas appliance must be tested to confirm it is operating safely before it is reconnected.
- Repair or replacement of the faulty component. Whether a pipe section, a fitting, or the appliance itself.
In older properties, the gasfitter may recommend a broader inspection to identify other sections approaching the end of their serviceable life. Attempting to restore the gas supply yourself without this inspection is both dangerous and illegal in Victoria.
Gas Safety Inspections: When and Why
Gas appliances and pipework do not need to fail completely before they become a safety risk. Regular servicing catches deterioration early. Energy Safe Victoria recommends gas heaters be serviced every two years. Other appliances should be checked if they show any signs of abnormal operation.
Signs that warrant a service call
- Orange or yellow flames instead of a clean blue flame on any burner.
- A burning smell when an appliance is in use.
- Appliances that are slow to ignite or fail to ignite on the first attempt.
- Visible rust, discolouration, or physical damage to pipework or connections.
- Moving into a property where you do not know when the gas system was last inspected.
- Properties in Melton, Bacchus Marsh, and Caroline Springs that have not had a formal gas inspection in a decade or more — an elevated risk of undetected wear exists even if the system appears to be working normally.
Carbon Monoxide: The Invisible Risk
Carbon monoxide is produced when gas appliances burn fuel incompletely. It is colourless, odourless, and tasteless. Unlike a gas leak, you cannot smell it. It is commonly called the silent killer because it can build up to dangerous concentrations without any warning signal.
Causes, symptoms, and prevention
- Causes: A dirty burner, a blocked or damaged flue, or insufficient ventilation around the appliance all lead to incomplete combustion and carbon monoxide production.
- Symptoms: Headache, dizziness, nausea, shortness of breath, confusion, and loss of consciousness at higher concentrations. Symptoms are similar to flu and are often dismissed — particularly in winter when heaters are in heavy use.
- Key indicator: Multiple household members experiencing similar symptoms that improve when leaving the home is a strong sign of carbon monoxide and requires immediate action.
- Prevention: Install a carbon monoxide alarm in rooms where gas appliances are used. These are separate from smoke detectors and specifically detect CO rather than smoke or heat.
- Testing: New Image Plumbing and Gas provides carbon monoxide testing as part of a gas safety inspection, checking all appliances for incomplete combustion and verifying flues are clear and drawing correctly.
Gas Safety in Melbourne’s Western Suburbs
Homes across Melton, Bacchus Marsh, Caroline Springs, Deer Park, Rockbank, and the surrounding growth corridors vary significantly in age and the condition of their gas systems. Both new and established properties carry their own specific risks.
Risk profile by property type
- New builds: The most common issue is gas connections to appliances that were not fully verified during construction. A pre-occupancy gas check resolves this before your family begins using the appliances regularly.
- Established properties: Risks shift toward corroded pipework, degraded flexible connectors, and flues that have not been cleaned or inspected in years.
- Properties over 15 years old: A full system inspection is strongly recommended if the gas system has not been looked at in a decade or more.
If you have smelled something unusual near a gas appliance, if your bills have increased without explanation, or if your system has not been inspected in several years, do not wait for an obvious problem to develop.
Conclusion
Knowing what a gas leak smells like and how to respond will help keep your home and family safe. If you suspect a leak, act quickly and avoid anything that could create a spark. If you are unsure, it is best to have the gas system checked by a qualified professional.
Call New Image Plumbing and Gas on 0489 246 667 or submit our online form to arrange an inspection. We service Melton, Bacchus Marsh, Caroline Springs, and all surrounding Western Melbourne suburbs, 24 hours a day.
Frequently Asked Questions
What does mercaptan smell like exactly?
Mercaptan is described as smelling like rotten eggs, sulphur, or decaying cabbage. It is a distinctively unpleasant chemical odour added to natural gas and LPG specifically because it is so recognisable at extremely low concentrations. Even a faint trace of this smell indoors should be taken seriously and investigated by a licensed gasfitter.
Is LPG more dangerous than natural gas?
Both are dangerous in the right conditions. LPG is heavier than air and sinks to floor level, accumulating in poorly ventilated spaces without being immediately obvious. Natural gas is lighter than air and disperses upward. Both are flammable and neither should be treated as less serious than the other.
Can I turn my gas back on myself after an emergency shutoff?
No. After any gas leak or emergency shutoff, a licensed gasfitter must inspect the system and confirm it is safe before the gas supply is restored. Restoring gas yourself without an inspection is both dangerous and illegal in Victoria. The gasfitter will conduct a pressure test, check all appliances and connections, and only then turn the gas back on.
How often should gas appliances be serviced?
Energy Safe Victoria recommends gas space heaters be serviced every two years. Cooktops, hot water systems, and ovens should be inspected if they show any signs of abnormal operation such as orange or yellow flames, unusual smells, difficulty igniting, or poor performance. Older properties with gas appliances that have not been serviced in several years should have a full system check.
Does homeowner’s insurance cover gas leak damage?
It depends on the policy. Sudden and accidental damage from a gas leak or resulting fire is typically covered. However, gradual damage from a slow, undetected leak may be excluded if the insurer can argue it could have been identified with reasonable maintenance. Always check your policy and contact your insurer promptly after any gas incident.
Are gas leaks more common in certain seasons?
Gas appliances are used more heavily during Melbourne winters, so problems with heaters and hot water systems are most commonly detected then. Leaks themselves are not particularly seasonal — corrosion and fitting failure happen year-round. What changes in winter is that faults developing during warmer months often become apparent the first time a heater is switched on. Booking a pre-winter gas safety check in April or May is a sensible habit.
