Knowing how to recognise the signs of a gas leak and what to do if you suspect one can save lives. Natural gas used in UK homes is odourless in its natural state, but a distinctive smell is added specifically to make leaks detectable. This article covers the warning signs, detection methods, and the correct emergency response.

The Smell of Gas

The gas supplier adds a chemical called mercaptan to natural gas to give it a distinctive smell, often described as similar to rotten eggs or sulphur. If you detect this smell in your home, take it seriously even if it seems faint. A faint smell can indicate a small leak that is still dangerous. The absence of smell does not guarantee the absence of gas, as some leak situations or some types of gas do not produce a detectable odour.

Other Warning Signs

Beyond smell, other signs that may indicate a gas leak include a hissing or whistling sound from a pipe or appliance, dead or dying plants in an area where the underground supply pipe runs, bubbles appearing in a wet patch of ground in the garden over the supply pipe route, and in severe cases, symptoms of carbon monoxide poisoning such as headache, dizziness, or nausea when indoors. Condensation or frost on gas pipes or connections can also indicate a problem.

Soapy Water Test for Connections

For suspected small leaks at gas connections that you can see, applying a solution of washing-up liquid and water to the joint with a brush or cloth will produce bubbles if gas is escaping. This is a safe visual detection method that plumbers and engineers use to confirm a seal. Do not use this method if you can already smell gas strongly in the area or if you suspect a major leak.

What to Do If You Smell Gas

Do not turn any electrical switches on or off, including light switches, as the spark can ignite gas. Do not smoke or use any naked flame. Open windows and doors to ventilate the space. Do not operate any electrical equipment. Turn off the gas at the main emergency control valve, which is typically beside the gas meter. Leave the building immediately and do not re-enter. Call the National Gas Emergency number: 0800 111 999. This number is available 24 hours a day, seven days a week and is free to call. Stay away from the building until the engineer has attended and confirmed it is safe.

Summary

Gas leaks are most commonly detected by the added odorant smell or a hissing sound. A soapy water solution reveals small leaks at visible connections by producing bubbles. If a gas leak is suspected, do not operate any electrical switches, open windows, turn off the gas at the meter, leave immediately, and call 0800 111 999. Install carbon monoxide alarms in all rooms with gas appliances.