Gas Leaks Outside the Home

Gas leaks are not limited to inside buildings. Leaks in underground supply mains, at above-ground meter points, and in outdoor garden pipework all pose hazards — including explosion risk and the potential for gas to enter buildings through foundations, drains, or vents. Knowing how to recognise an outdoor gas leak and what to do about it is as important as recognising an indoor one.

Signs of an Outdoor Gas Leak

Outdoor leaks may not produce the same visible or olfactory signals as indoor leaks:

Sign	Description
Gas smell outdoors	Persistent rotten egg / sulphur smell in a street, garden, or area without obvious source
Hissing or roaring from underground	Audible sound from ground level, near buried pipe locations
Unusual plant death	A linear strip of dead plants or grass following the line of a buried pipe
Frost patterns	In cold weather, differential frost patterns on ground over gas pipes
Dirt or dust blowing	Ground disturbed near buried lines; small craters or bubbling
Bubbling water	In ditches, puddles, or streams near pipeline routes
Dead insects	Unusual insect mortality near a pipe route

Outdoor gas leaks can travel through soil and enter buildings through floor penetrations, cable conduits, or foundation cracks. A gas smell inside a building is not always from indoor appliances — it may be from an outdoor leak entering.

On-Street Gas Smells

If you smell gas in a street, near a junction, or in any outdoor public space:

1. Move away from the area — do not stop near the smell.
2. Keep others away — warn passers-by and prevent anyone from using a car, motorbike, or lighter in the area.
3. Call the gas emergency number — in the UK: 0800 111 999. This is a 24/7 number staffed specifically for these reports.
4. Do not create ignition sources in the area — no smoking; no starting vehicles.
5. Alert nearby residents or businesses that there is a suspected gas leak so they can evacuate.
6. Stay in the area only to direct emergency services if requested — do not enter any enclosed spaces downwind of the suspected leak.

Meter Box Leaks

The gas meter box — typically recessed into an external wall — contains connections that can develop faults:

1. Smell near the meter box — sniff carefully at the edges of the box on an external wall; a persistent gas smell here is a meter box fault.
2. Do not attempt to repair the meter yourself — only authorised gas engineers can work on the meter.
3. Call the gas emergency number — provide your address and describe that the smell is near the meter box.
4. If the meter box is on fire — call 999 (UK) or 911 immediately; this is a gas emergency plus a fire.

Underground Pipeline Damage

Construction work, vehicle impact on road surfaces, and ground movement can damage buried gas supply pipes:

If you are present when a pipeline is struck:

1. Stop work immediately.
2. Evacuate everyone from the immediate area.
3. Call the gas emergency number and 999/911.
4. Do not attempt to seal or repair the damage.

If you suspect a buried pipeline has been damaged without an obvious cause:

• Signs: sudden strong gas smell after nearby construction; ground subsidence
• Report to the gas emergency number immediately

Gas Smell Entering the Building from Outside

If you smell gas inside your home but cannot locate any indoor source:

1. The leak may be entering from underground.
2. Evacuate as you would for an indoor leak — do not stay to investigate.
3. Call the gas emergency number — report that the smell is inside the building but you cannot find an indoor source.
4. Do not re-enter until gas engineers have confirmed the source and it has been rectified.

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Quick Reference

Situation	Action
Gas smell in street or public space	Move away; call 0800 111 999 (UK); prevent ignition
Gas smell near meter box	Call gas emergency number; do not repair yourself
Pipeline struck during work	Stop work; evacuate; call emergency number and 999
Gas entering building from underground	Evacuate; call gas emergency number
All outdoor gas leaks	No smoking; no vehicle starts near area; keep others away