Gas leaks

Gas leaks can occur from faulty gas appliances or pipework. Natural gas and Liquid Petroleum Gas (LPG) aren’t poisonous, but both can lead to fires and explosions. To make it easier to detect a gas leak, a harmless chemical is added to gas which makes it easy to smell.

To help avoid a gas leak in your home you could check your gas pipework - if it is easy to access and safe to do so. Make sure you get any damage or signs of corrosion, such as rusting or green discolouration on copper pipework checked by a Gas Safe registered engineer.

What causes a gas leak?

Gas leaks in the home are usually the result of poorly fitted, badly maintained or faulty appliances like boilers and cookers.

If your appliance is badly fitted, gas can escape from the gas hose that leads into your appliance or from around the seal. You should always make sure your gas appliances are installed by an accredited Gas Safe registered engineer (previously CORGI).

If your appliances are a bit older and you’re having them serviced, again make sure you always use a Gas Safe registered engineer. You should also be extra careful with old or second-hand appliances, particularly if you are moving into a new property or renting.

What to do if you smell gas

If you think you can smell gas and may have a gas leak, or are worried about one of your appliances, call the Gas Emergency Service on 0800 111 999. You can also call this number if you’re worried about one of your appliances giving off carbon monoxide (CO), but remember that you cannot see, smell or hear CO.

If you smell gas but you are not in immediate danger:

  • Call National Grid's Gas Emergency Service Freephone number 0800 111 999 – from a landline at a different property or using a mobile phone, away from the leak
  • Open all the doors and windows
  • Don’t smoke, light a match or any other naked flame
  • Don’t turn lights on or off and avoid using other electrical switches and appliances as this could trigger an explosion.

If you or your family are in immediate danger, exit the premises immediately and call 0800 111 999.

How to turn your gas off at the meter in an emergency (if it is safe to do so)

If the gas supply is in a cellar or basement then don’t turn it off. Evacuate the building and do not re-enter as the concentration of gas may trigger an explosion, from even a small spark.

If your meter is easy and safe to locate, to turn off your gas supply, first locate the gas emergency control valve, which you should find next to the meter. In newer houses, the gas meter and isolation valve are often outside in a meter box. If not, try looking under the stairs, beneath the kitchen sink or in the garage. We suggest you find out where your gas meter and emergency control valve is, so you’re prepared in case of an emergency.

To turn off the gas supply, simply turn the handle a quarter turn so the lever is at 90 degrees to the upright gas pipe.

Remember, if you smell gas, extinguish any sources of ignition and ventilate the building by opening doors and windows. Do not turn any electrical switches on, don’t smoke and don’t use your mobile phone.

If you are in immediate danger evacuate the building and then call the Gas Emergency Service on 0800 111 999.

What happens if a gas leak isn't dealt with?

A gas leak can lead to fires and explosions and if gas is not burned completely it can lead to carbon monoxide poisoning. According to Gas Safe Register (GSR), in the past three years one in six homes inspected by the organisation had an unsafe gas appliance. If left unchecked, these appliances could have led to fires, explosions and poisoning.

Checking your appliances for leaks

All of your gas appliances, including your boiler, cooker and fire should be safety checked once a year and serviced regularly according to manufacturer’s instructions. If you smell gas or start feeling ill when gas appliances are in use, it is important to act quickly to protect yourself and your family.

Gas fires and explosions

Gas is highly combustible. Correctly fitted and maintained gas appliances ensure that gas is burned in a safe and controlled way to heat our homes and to cook with. If gas leaks from a faulty appliance or pipework it can spread quickly and there is a risk of it igniting, causing a fire or an explosion.

Carbon monoxide poisoning

Incorrectly fitted or poorly maintained gas appliances can produce a highly poisonous gas called carbon monoxide (CO) which can leak into your home.

You can’t see it, taste it or smell it but it can kill quickly and with no warning. It can also cause serious long term health problems such as brain damage. The symptoms of CO poisoning are similar to flu or food poisoning, so often people don’t know they’re actually suffering from CO poisoning.

The most common symptoms are:

  • Headaches
  • Dizziness
  • Nausea and vomiting
  • Tiredness and confusion
  • Stomach pain
  • Shortness of breath and difficulty breathing

For more information about CO poisoning, the symptoms, how to detect a leak and what to do if you suspect a leak, visit our carbon monoxide safety pages.