If you discover an unexpected smell of gas in your home, it is important to take action quickly to establish whether or not there is a gas leak and make sure that there is no risk to yourself or other occupants. Although the natural gas that is supplied to homes in the UK isn’t poisonous, it is highly flammable and can cause fires and explosions. If it is not burned properly, for example because of a faulty appliance, it can also cause extremely dangerous carbon monoxide (CO) which you cannot see, taste or smell.

In its natural state, natural gas is odourless. For this reason, a special harmless chemical is added to give it the easily recognisable smell that most people associate with gas.

So what should you do in the event of a suspected gas leakage? Here is some essential advice.

What to do is you suspect a gas leak at home© xshot / Shutterstock.com

What causes gas leaks in the home?

Although gas leaks in the home are relatively rare, there are some common causes that are behind the vast majority of cases. A gas leak within a property can only occur if you use gas for heating, warming your water or cooking. If this is the case, then there is a possibility that there may be a gas leak within your house or flat.

If you do not have any gas appliances, then it is likely that any gas leak is outside the property. In this situation, call the Gas Emergency Service on 0800 111 999 from a safe distance, inform them of the location where you smelt gas and follow the advice given.

If there is a possibility that the gas leak may originate from within the property, consider the following potential causes:

Corroded pipes

Corroded pipes can be an early sign of a gas leak and there are visual clues that may appear long before there is enough of a leak to smell it. Look out for any obvious damage to pipes, as well as rust and green discoloration on copper pipes. If you do discover any of these indicators, it is recommended that you seek immediate advice from a Gas Safe (previously known as CORGI) registered engineer. Check your pipework once or twice a year for peace of mind.

Badly fitted appliances

Another common cause of residential gas leaks is poorly fitted appliances, most commonly gas cookers and boilers. If the appliance was badly fitted in the first place, or has been able to move, then there is a risk that the seal may be damaged, allowing gas to leak. To help avoid this danger, be sure to have all appliances installed by a Gas Safe engineer as required by law, and consider having any second hand appliances inspected prior to purchase.

If you have recently moved into a rented or purchased property, make sure that the documentation is available for the most recent gas safety check and if in doubt make arrangements to have an inspection carried out as soon as possible.

Faulty appliances

Faulty gas appliances in the home are extremely dangerous. As well as gas leaks, they can also cause carbon monoxide if they do not burn the gas properly. There are some simple ways to protect yourself from the danger of faulty appliances:

  • Ensure that all gas appliances including cooker, boiler and fires are serviced once a year by a Gas Safe engineer.
  • Have appliances regularly serviced by an accredited or trained engineer as recommended in the documentation.
  • Discontinue use and replace appliances immediately if you are advised they are no longer safe for use.
  • Ensure you have carbon monoxide detectors fitted in your home and conduct tests at the recommended frequency. Be sure to replace them by the advised date.

There are also some tell-tale signs to be aware of that may indicate something is not right with your gas appliances. The most common signs of carbon monoxide poisoning are:

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

If you suspect that there is a carbon monoxide leak in your house, follow the same procedure as for a suspected gas leak, as described below. If you or other family members experience any of the symptoms of poisoning, seek medical advice immediately. Call 111 for advice or 999 if you believe that the situation is life-threatening.

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I smell gas - what should I do?

The most important consideration if you suspect a gas leak is to make sure that nobody is in immediate danger. If you believe that you or your family are in immediate danger, evacuate the building immediately and call the Gas Emergency Service on 0800 111 999.

If you are satisfied that there is no immediate risk to yourself and others, then you should take the following steps:

  • Do not smoke, light a match or use any other naked flame.
  • Do not turn lights or any other switches on or off - these can cause a spark.
  • Do not use your mobile phone.
  • Evacuate the building.
  • Open all the doors and windows.

Once you have done this, and as long as there is still no danger, you should turn your gas supply off at the meter using the emergency control valve. In most modern properties, this will be located in the meter box on the outside of the property. 

Older properties may have it located elsewhere. In any case, it is always advisable to familiarise yourself with the location of the gas isolation valve for your property. Once you have found the control valve, rotate it by 90° to turn off the supply.

If your gas supply control valve is located in the cellar or basement then you should not enter until you are sure that the gas has cleared as it may have built up to extremely dangerous levels.

After following all of the above steps, it is recommended that you call the Gas Emergency Service on 0800 111 999. Use a neighbours phone or a mobile phone if you are a safe distance from the leak. Do not attempt to use any landline or mobile phone within the property that is affected.

Preventing gas leaks

In reality, gas leaks in the home are a very rare occurrence and not something you should generally worry about. Overall, gas is an extremely safe, efficient and relatively clean energy source that is highly popular. 

However, the best way to avoid any danger from gas leaks in your house or flat is of course to prevent them from occurring by ensuring that you have your boiler and other gas appliances inspected and serviced annually by a qualified professional and replace your boiler when it needs to be modernised or as otherwise advised.

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