Gas leaks: what to do if you smell gas in your home

In the event of a gas leak or gas emergency, here’s what to do and how to contact the National Gas Emergency number.

Kim Jones
Kim Jones
Updated 7 February 2022  | 3 mins read

Gas appliances in the home, like boilers, hobs and ovens, can pose potential risks, including:

  • Leaks
  • Fires
  • Explosions
  • Carbon monoxide poisoning

If you smell gas, or suspect a gas leak, you need to act fast.

Key points

  • If you smell gas or suspect a gas leak, you should call the National Gas Emergency number - 0800 111 999
  • They can send a gas engineer out to your home to make it safe
  • Always use a Gas Safe registered engineer to fit gas appliances and get them checked annually

Detecting a gas leak

Household gas is naturally unscented, but energy suppliers add an odourous chemical to it, so it doesn’t go unnoticed should a leak occur. It smells a little like sulphur or rotten eggs.

Carbon monoxide has no smell but breathing in too much of it can prove fatal. That’s why it’s vital you install carbon monoxide alarms in your home to alert you to any dangerous leaks.

Other signs of a gas leak are hissing sounds coming from equipment, even when switched off, and dead or dying houseplants that have normally thrived. You may also notice higher than usual gas usage.

Unexplained symptoms including dizziness, headaches, nausea and breathing problems could also indicate that there’s a leak in your home.

What should I do if I smell gas in my home?


  • Open doors and windows to let in fresh air and let out the gas
  • Turn off the gas at the mains. According to British Gas, in newer houses, the isolation valve is normally outside in a meter box with the gas meter. If it's not there, it could be under the stairs, beneath the kitchen sink or in the garage. Turn the handle a quarter, so the lever is at 90 degrees to the upright gas pipe
  • Call the National Gas Emergency number (0800 111 999). It’s free and available 24 hours
  • Extinguish any naked flames
  • Leave your home
  • If you live in a flat or semi-detached or terraced property, it’s a good idea to let your neighbours know that you have a gas leak


  • Switch on or off anything electrical. Likewise, don’t use your mobile phone, doorbell or anything that can cause a spark
  • Smoke or strike a match

What do I do if my carbon monoxide alarm sounds?


  • Switch off fuel-burning appliances, open doors and windows to ventilate the house
  • Leave the house
  • Call the National Gas Emergency number (0800 111 999)
  • Seek medical help and advice


  • Go back into the property until you’ve had advice from the emergency services

Can I prevent a gas leak?

  • Some gas leaks happen because gas appliances have been installed incorrectly. Always be sure to get appliances installed by a Gas Safe registered engineer
  • Get your appliances serviced and checked by a Gas Safe registered engineer at least once a year
  • If you live in rented accommodation, your landlord is legally required to arrange annual safety checks on all gas appliances and installations they own in the property.
  • Subsequently, your landlord should provide you with a gas safety record for the property
  • Get a gas detector alarm installed by a Gas Safe registered engineer
  • Also get Carbon Monoxide (CO) detectors installed

Can a gas leak make you ill?

Sometimes, a gas leak can cause headaches, dizziness and nausea.

If you have mild symptoms they should go away when you leave the home, but it’s still a good idea to see a doctor.

Breathing in carbon monoxide, meanwhile, can lead to poisoning, which can be fatal.

Symptoms can include tension headaches, extreme fatigue, sickness, dizziness and confusion, stomach pain and difficulty breathing.

The more of the gas you inhale, the worse your symptoms will get.

Eventually you may lose balance, vision and consciousness.

If you think you’ve been exposed to low levels of carbon monoxide, you should see your GP.

If you feel you’ve been exposed to high levels, then you should go to A&E immediately.

If someone has collapsed or is displaying severe symptoms, call 999.

Do you get charged for a gas leak call out in the UK?

Calling the National Gas Emergency number to report a gas leak is free.

An emergency gas engineer will be sent, free of charge, to ‘make safe’ your property.

They won’t repair appliances or pipework, though, that’s something you’ll need to arrange and pay for yourself. Always use a Gas Safe registered engineer.

How much does fixing a gas leak cost?

Of course, the price will vary depending on the price of materials and how long it takes to do the repair, but it’s usually costs around £350 on average to repair a gas pipe.

Whatever the cost, it’s something you need to get done by a professional Gas Safe registered engineer.

Trying to fix the problem yourself, or leaving it broken, is a definite no-no. Gas repairs are extremely dangerous and best left to the professionals.

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