20 Oct 2026 · 3 min read
What to do if you smell gas in your home or at a rental property
By Carlton Fuller · Founder & Master Gas Engineer, 30 years' experience
Gas leaks are rare, but the correct response in the first few minutes matters. If you or a tenant can smell gas in a property, follow this sequence immediately.
Immediate steps
- ◆Do not switch any electrical switches on or off - this includes lights, plugs and appliances
- ◆Do not use a mobile phone inside the building - go outside first
- ◆Do not use naked flames or smoke
- ◆Open windows and doors to ventilate the property
- ◆Turn off the gas supply at the meter - the emergency control valve is usually a lever next to the gas meter
- ◆Leave the building and stay outside until the all-clear
Who to call
Call the National Gas Emergency Service on 0800 111 999 - free, 24 hours. Make this the first call for any suspected gas escape, before your landlord, plumber or energy supplier. The emergency line will despatch a Gas Distribution Network engineer to make the scene safe.
What happens next
A National Gas Emergency Service engineer will attend and make the gas supply safe. They will advise whether the property can be reoccupied. Any gas appliance or pipework work needed after that point must be carried out by a Gas Safe registered engineer before the gas supply is restored.
For landlords and letting agents
If a tenant smells gas, your legal obligation is to respond immediately. Once the emergency service has attended and made the property safe, arrange for a Gas Safe engineer to carry out a full inspection before any gas appliance is used. Document the incident and keep records alongside your CP12 history. Do not pressure tenants to return until a Gas Safe engineer has confirmed the property is safe.
After a gas incident, we can carry out the safety inspection and get your property back into service.
Book a post-incident inspectionFrequently asked
What does a gas leak smell like?
Gas is naturally odourless but a chemical called mercaptan is added specifically to make it detectable. It smells like rotten eggs or sulphur. If you can smell it, treat it as a leak immediately.
Can I use my boiler if I smelled gas but the smell has gone?
No. The smell dispersing does not mean the leak has stopped. It may mean the gas has built to a dangerous concentration or dissipated temporarily. Do not use any gas appliance until a Gas Safe engineer has checked the installation.
Is carbon monoxide the same as a gas leak?
No. Carbon monoxide is produced by incomplete combustion in gas appliances and has no smell. A CO alarm is your only warning. Fit a CO alarm on every floor. If it sounds, treat it exactly like a gas leak.
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Need a Gas Safe engineer?
Call 07956 876156 or request a callback - we cover South London and Surrey.