⚠️ If you can smell gas right now: call the National Gas Emergency Service on 0800 111 999 (free, 24 hours). Leave the property immediately and do not use any electrical switches, naked flames or your phone until you are outside.
Smelling gas in your home is one of those situations where it pays to know exactly what to do before it happens. The good news is that natural gas in the UK has a distinctive smell added to it precisely so you can detect a leak — so your nose is your first and most important warning system. The bad news is that in a moment of panic, it's easy to do exactly the wrong thing.
Here's a clear, step-by-step guide to what you should do if you smell gas, and what you should absolutely avoid.
Step 1 — Don't Panic, But Act Quickly
Stay calm and act decisively. A gas smell doesn't automatically mean there's a large leak or that an explosion is imminent — but it does need to be taken seriously immediately. The faster you act on the steps below, the safer everyone will be.
Step 2 — Do Not Touch Any Electrical Switches
Do not turn any light switches on or off. Do not press any buttons on appliances. Do not use a torch with a conventional switch. Gas can ignite from the smallest electrical spark — even the tiny arc produced by flicking a light switch. Leave everything exactly as it is electrically.
Step 3 — Do Not Use Your Mobile Phone Indoors
Wait until you're outside before making any calls. Mobile phones produce radio frequency energy and, in extreme concentrations of gas, there is a theoretical risk of ignition. Get outside first, then call.
Step 4 — Open Windows and Doors If It's Safe to Do So
If you can do so quickly without operating any electrical switches, open windows and external doors to ventilate the property. Don't spend time searching for the source of the smell — just open what you can reach and leave.
Step 5 — Turn Off the Gas at the Meter (If You Know Where It Is)
The gas meter and emergency control valve (ECV) is usually located near the front of the property — in a cabinet outside, under the stairs, or in a cupboard near the front door. The ECV is a handle or lever on the gas pipe near the meter. To turn the gas off, turn it so the handle is at right angles to the pipe (perpendicular = off; in line with the pipe = on).
If you don't know where your meter is, or you can't get to it quickly, don't spend time looking for it. Just leave.
Step 6 — Leave the Property
Get everyone — including pets — out of the building. Don't stop to collect belongings. Leave the front door open as you go if possible, to help ventilation.
Step 7 — Call the National Gas Emergency Service
Once you're outside and away from the building, call 0800 111 999. This line is free and operates 24 hours a day, 7 days a week. They will ask for your address and a description of what you can smell, and they will arrange for an engineer to attend — usually within the hour for a suspected gas leak.
Do not re-enter the property until you've been told it's safe to do so.
What NOT to Do
- Do not light a match, candle or cigarette
- Do not use any electrical switches or appliances
- Do not use your mobile phone inside the building
- Do not attempt to find the source of the leak yourself
- Do not try to repair anything yourself — all gas work must be carried out by a Gas Safe registered engineer
- Do not re-enter until officially told it is safe
What Does a Gas Leak Actually Smell Like?
Natural gas is odourless in its raw form. Gas suppliers are required by law to add a sulphur-based odorant — usually ethyl mercaptan — which gives it that distinctive eggy, rotten sulphur smell. You'll know it when you smell it.
If you smell something similar but are unsure — perhaps it's faint, or you only notice it in one room — err on the side of caution. Ventilate the property, turn the gas off at the meter, and get it checked before you use the boiler or any other gas appliances again.
What Happens After the Emergency Service Visits?
The National Gas Emergency Service will isolate the source of the leak and make the property safe. Depending on where the fault is, they may cap off a supply or disconnect an appliance. They will not carry out repairs themselves — that's where a Gas Safe registered engineer comes in.
Once the property has been declared safe and you've been told what was found, give us a call. We can attend to repair the fault, reconnect appliances, and carry out any safety checks required before your gas supply is restored to full use. All our engineers are Gas Safe registered (No. 3880) and we carry out all gas work to the required standards.
Carbon Monoxide — A Different but Related Risk
Worth mentioning here: carbon monoxide (CO) is produced by incomplete combustion in gas appliances. Unlike a gas leak, you cannot smell it — it is completely odourless. Symptoms of CO poisoning include headaches, dizziness, nausea and confusion, particularly if they improve when you leave the house.
Every home with a gas boiler should have a carbon monoxide detector — preferably one that meets British Standard EN 50291. They're inexpensive and widely available. If your CO alarm sounds, treat it the same way as a gas smell: get out, call 0800 111 999, and don't go back in until it's safe.
We check for signs of combustion issues and CO risk as part of every annual boiler service. If you haven't had your boiler serviced recently, it's worth getting it done. Call us on 07961 169 681 and we'll book you in.