What to Do If You Smell Gas at Home

The steps, in order

Gas in the UK has a strong smell added to it deliberately, precisely so that a leak is noticed. If you can smell it, treat it as real until someone qualified has checked.

• Do not use anything that could make a spark. Leave light switches, doorbells and plugs as they are, whether they are on or off. Do not light a match, a cigarette or the hob.
• Open doors and windows to let the gas disperse.
• Turn the gas off at the meter if it is safe and easy to reach. The lever sits on the pipe next to the meter. When the handle is in line with the pipe the gas is on. Turn it a quarter turn so the handle is across the pipe, and the gas is off.
• Get everyone out if the smell is strong, if you cannot turn the gas off, or if anyone feels dizzy, sick or has a headache.
• Call 0800 111 999 from outside, or from a phone well away from the smell. Tell them where you are and how strong the smell is.
• Stay out until the emergency engineer arrives and says it is safe to go back in.

If you live in a flat and the smell is in a shared hallway or stairwell, or you cannot find your meter, do not go looking for it. Leave, and call 0800 111 999 from outside.

Where is the gas meter, and how do you turn it off?

In a London house the gas meter is most often in a box on an outside wall, in a cupboard under the stairs, in a cellar, or under the kitchen sink. In a flat it may be in the flat itself or in a locked meter cupboard in the common parts. The handle you need is on the pipe coming into the meter, before it.

It is worth finding the meter and the handle now, on a calm day, in the same way it is worth knowing where your water stopcock is. Our guide on where is my stopcock covers the water side. Check that the handle turns. If it is seized solid or missing, do not force it, but mention it to an engineer next time one is in the house.

What happens after you call 0800 111 999

The emergency line is run for the gas network, not for your energy supplier, and it covers everyone regardless of who you pay your bill to. The adviser will ask where the smell is, how strong it is, and whether you have turned the gas off. They then send an emergency engineer.

The emergency engineer is there to make the situation safe, not to repair appliances. They will look for where the gas is escaping. If the leak is on the network side, such as the pipe in the street or up to the meter, the network repairs it. If it is on your side of the meter, on internal pipework or an appliance like a boiler, cooker or gas fire, they will isolate that appliance or turn off the supply and put a warning label on it. It then stays off until a Gas Safe registered engineer has repaired it.

That is often the point where you are left without heating or hot water. Do not turn a supply or an appliance back on that has been capped or labelled as unsafe. It is dangerous and it is illegal to use it until it has been repaired.

How to check for a gas leak without putting yourself at risk

A homeowner should not go hunting for a gas leak with a flame, a lighter or a spray, and should not take appliances apart. What you can safely do is notice the signs, and pass them on.

• The smell itself, often described as rotten eggs or cabbage, strongest near one appliance or one pipe.
• A hissing or whistling sound near a gas pipe or appliance.
• A hob flame that burns yellow or orange and lazy instead of crisp and blue.
• Black or brown sooty marks around a boiler, gas fire or cooker.
• A gas bill that has jumped for no obvious reason.
• Dead or dying plants over the line of a buried gas pipe outside.

Carbon monoxide has no smell

A gas leak and carbon monoxide are two different dangers. A leak is unburnt gas escaping, and you can smell it. Carbon monoxide is produced when gas burns badly, for example in a boiler or gas fire that needs servicing or has a blocked flue, and it has no smell, no colour and no taste.

The signs are headaches, dizziness, nausea, tiredness, breathlessness and confusion, often better when you are out of the house and worse when you come back. If you suspect it, get into fresh air, turn off the appliance if it is safe to, call 0800 111 999, and get medical advice. An audible carbon monoxide alarm in any room with a gas appliance is the only reliable warning, and it costs very little.

Smells that are not gas

Not every eggy smell in a house is a gas leak, but you should still treat one as a leak until it is ruled out. Once the emergency service has checked and found no gas, these are the usual culprits.

• A rotten egg smell only from the hot tap. This comes from a reaction inside the hot water cylinder, not from gas, and our guide on hot water smells like rotten eggs explains the cause and fix.
• A drain or sewer smell from a sink, shower or floor gully where the water trap has dried out.
• A hot, burning or fishy smell from an electrical fitting. Turn that circuit off at the consumer unit and get an electrician.
• A new boiler or radiators running for the first time after summer, which can give off a dusty smell for a short while.

Getting the gas back on

Once the emergency engineer has made it safe, you need a Gas Safe registered engineer to find and repair the fault, test the installation and put the supply or appliance back into service. Check the person who turns up is on the register and qualified for the appliance in question. Our gas safe register check guide explains how in a couple of minutes.

If the fault was on the boiler and you have been left with no heating or hot water, call us on 020 4652 5111 or send an enquiry. We have 20 engineers across London and can diagnose the boiler and restore the heating and hot water once the supply is safe. Our boiler diagnosis page explains what that visit involves, and our rate is on the pricing page, agreed before we attend. We are not an emergency gas service: if you can smell gas right now, stop reading and call 0800 111 999 first.