What to do if you smell natural gas inside your house

A rotten-egg or sulphur-like smell indoors can indicate a natural gas leak. Treat it as an emergency, even if the odour seems faint, comes and goes, or appears near only one appliance. Gas can ignite when it mixes with air, while a poorly ventilated room can allow fumes to build up quickly.

The safest response is simple: avoid creating a spark, get everyone outside, and call for help from a safe location. The process is broadly the same whether you live in a Melbourne terrace, a Brisbane unit, a regional New South Wales home, or a property connected to a local municipal network in California.

Act immediately inside the house

Do not switch lights on or off, start an appliance, use a landline, light a cigarette, strike a match, or start a car in or near the building. Avoid touching electrical plugs, doorbells, garage doors and mobile phones until you are outside. A tiny spark can ignite leaked gas.

Warn other people calmly and leave by the quickest safe route. If a door or window is already open, leave it that way, but do not stop to ventilate the property if doing so requires operating a switch or moving towards the suspected leak. Take children, visitors and pets with you, provided they can leave without delay.

Do not search for the source, try to repair a cooker or heater, or turn the gas supply back on. If you can reach the gas meter or cylinder isolation valve without passing through the odour or putting yourself at risk, you may shut it off. Never delay evacuation to do this.

Call from a safe location

Once everyone is well away from the building, call Australia’s emergency number, Triple Zero (000), if there is an immediate danger, a fire, an explosion risk, anyone feels unwell, or the leak cannot be controlled. Tell the operator that you suspect a gas leak and give the exact address.

You should also contact the gas distributor’s emergency number, which is different from the retailer printed on your bill. In Australia, the distributor owns and maintains much of the network, while a retailer handles plans, billing and account questions. Your distributor may be Jemena, AusNet, Australian Gas Networks, Evoenergy, APA or another regional operator.

If you use LPG bottles or an LPG tank rather than mains natural gas, contact the supplier or emergency service listed on the cylinder, tank paperwork or account. Do not assume a mains-gas distributor is responsible for bottled gas.

Keep these actions handy

Write the emergency steps somewhere accessible, such as beside the front door or in a household safety folder. Keep the gas distributor’s number, LPG supplier details and your full address available, but do not go back inside just to find them.

If you smell gas:

• Move everyone outdoors immediately.
• Avoid flames, switches, vehicles and phones near the building.
• Call 000 and the gas distributor from a safe location.
• Stay outside until emergency or gas personnel say it is safe.

Do not:

• Smoke, light a match or use a lighter.
• Operate lights, fans, appliances or garage doors.
• Investigate the leak or attempt a repair.
• Re-enter for phones, pets or belongings.

Recognise symptoms and secondary hazards

Breathing gas in a poorly ventilated room can cause headache, dizziness, nausea, weakness or confusion. Carbon monoxide is a separate danger produced by incomplete combustion from faulty heaters, boilers, fireplaces or other fuel-burning appliances. It has no smell, so feeling unwell around a gas appliance should be treated seriously even when there is no rotten-egg odour.

If someone has collapsed or is struggling to breathe, tell the 000 operator immediately. Move the person into fresh air only if you can do so without exposing yourself. Do not re-enter the house to rescue someone when gas may still be present; trained responders have the equipment and procedures to do this safely.

A gas leak can also affect nearby properties, shared corridors and underground services. In a block of flats, alert neighbours from outside rather than activating an intercom or knocking on doors from inside the affected area. In a rural property, keep vehicles, generators and machinery away from the suspected leak.

Wait for an authorised safety check

The gas distributor, fire service or licensed gasfitter must inspect the installation before anyone returns. Their assessment may cover the meter, pipework, regulator, flue, cooktop, hot-water system, heater and ventilation. Do not relight pilot lights or reconnect appliances yourself.

For a rental property, notify the agent or landlord after the emergency call has been made. The owner is generally responsible for arranging repairs and ensuring fixed gas appliances are safe, while tenants should not carry out gas work. Only a licensed gasfitter should disconnect, repair, install or test gas appliances in Australia.

If the smell remains after the supply has been isolated, stay away and report it again. Gas can remain in wall cavities, drains, subfloors or enclosed outdoor areas. A completed repair is not the same as a completed safety clearance.

Reduce the chance of another leak

Have gas appliances serviced according to the manufacturer’s instructions and local requirements. Check that heater flues and ventilation openings are unobstructed, especially before winter in Canberra, Melbourne or the alpine regions. Never use an outdoor gas heater, barbecue or portable camping stove inside a home, garage, shed or enclosed balcony.

Install carbon monoxide alarms where recommended for fuel-burning appliances, but remember that a carbon monoxide alarm does not detect natural gas or LPG. Learn the difference between mains natural gas and LPG: LPG is commonly stored in cylinders and is heavier than air, so it can collect in low spaces, while natural gas generally rises. Both require immediate evacuation when a leak is suspected.

Municipal infrastructure information can help residents understand how utility, street and emergency services fit together; the Susanville Public Works site provides that kind of public-service context for the City of Susanville in California. Local Australian emergency contacts, however, should come from your own distributor, supplier or state authority.

Outdoor damage can sometimes threaten utility connections. For example, a fallen or low branch near a service line should be kept clear of, and guidance on reporting a low-hanging limb illustrates why infrastructure hazards should be reported rather than handled casually. If gas odour is present, leave the area first and contact emergency services.