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What to do if you smell gas: no switches, open windows, get out, call

In short: Don't touch light switches or make a flame. Open doors and windows, turn the gas off at the meter if it's safe, then leave and call the gas emergency number from outside. In the US, officials say leave first and don't touch any valves.

Co-authored by Sonia Abu Bakar✓, MSc Botany

By 6 min readPublisher: Saadat Rafiq

Last updated: 29 October 2026References

Set preferred
Illustration of a woman opening a kitchen window wide while holding her phone, with the front door open behind herIllustration

At a glance

Never
Light switches, doorbells, flames or a phone near the smell (SGN, Feuerwehr Lehrte, CPUC)
UK
0800 111 999, free, 24 hours (SGN)
Germany
112 and your gas supplier, from outside (Feuerwehr Lehrte)
US
Leave on foot, then 911 or your gas company (CPUC, NYC)
Pakistan
SNGPL 1199 and Rescue 1122 (APP)
Advice from
Gas networks, fire services and US regulators, read 29 October 2026
Checked
October 2026

Gas from a leak can catch fire from the smallest spark, such as a light switch or a doorbell (SGN, Freiwillige Feuerwehr Lehrte). The order below keeps sparks away while the gas clears. The advice differs a little between countries, so the table near the end shows each one.

Where is the smell?

Inside, faint

No sparks, air out, gas off, then leave and call. Start at Right now.

Strong, hissing, or in the cellar

Leave straight away. Go to Get out and call.

A gas cylinder (LPG)

Close it at the source. Go to Bottled gas.

Right now: no sparks, no flames

  1. Don't touch light switches, sockets or the doorbell.

    Illustration of a hand stopping just short of a light switch on a hallway wall
    Illustration

    Turning a switch on or off could ignite a gas leak (SGN). That includes plugging things in or out, and doorbells (Freiwillige Feuerwehr Lehrte). Leave lights as they are, even if it's dark (PSO).

  2. Put out any flame, and don't smoke or strike a match.

    Illustration of a hand turning a hob knob to off, with a box of matches pushed away to the side
    Illustration

    Put out all naked flames, and don't smoke or strike matches (Cornwall Fire and Rescue Service, SGN). Turn off gas appliances (Cornwall Fire and Rescue Service).

  3. Open doors and windows.

    Illustration of a woman pushing a window wide open, with a light breeze line coming in
    Illustration

    Fresh air lets the gas escape (SGN, Freiwillige Feuerwehr Lehrte). Do it by hand: don't switch on an extractor or exhaust fan (PSO).

    In the US, the California regulator says to leave first rather than stay to air the house.

  4. Careful: never go into a cellar or basement to reach the meter (SGN, Cornwall Fire and Rescue Service).

    Turn the gas off at the meter, if it's easy and safe to reach.

    Illustration of a hand turning the marigold lever on the pipe at a gas meter, with a curved arrow
    Illustration

    UK gas networks say to turn off the supply at the meter and any gas appliances (SGN). German fire brigades say to close the main shut-off valve (Freiwillige Feuerwehr Lehrte).

    The California regulator says the opposite for the US: don't try to control the leak by turning valves, just leave.

Get out and call

  1. Leave, and warn everyone in the building.

    Illustration of a woman knocking with her knuckles on a neighbour's front door in a stairwell
    Illustration

    Tell other people in the building and ask them to leave (Freiwillige Feuerwehr Lehrte). Knock with your hand instead of ringing the bell (California Public Utilities Commission). Go on foot, and don't start a car (California Public Utilities Commission).

    You should see: everyone outside, well away from the building.

  2. Call the gas emergency number from outside.

    Illustration of a woman standing on the pavement across the street from her house, making a phone call
    Illustration

    Don't use a phone inside or near the smell (Freiwillige Feuerwehr Lehrte, California Public Utilities Commission). Once you're away from it:

    • UK: 0800 111 999, free and open 24 hours (SGN). Call 999 for the fire service in an emergency (Cornwall Fire and Rescue Service).
    • Germany: 112 for the fire brigade, and your gas supplier (Freiwillige Feuerwehr Lehrte).
    • US: 911, then your gas company (NYC311, California Public Utilities Commission).
    • Pakistan: the SNGPL helpline 1199 (APP), and Rescue 1122 in an emergency (Rescue 1122).

  3. Stay out, and let the engineer in.

    Illustration of a gas engineer with a tool case arriving at the front door while the woman waits outside
    Illustration

    Keep people away if the area is cleared, and give engineers access straight away (Cornwall Fire and Rescue Service). Don't go back in until you're told it's safe.

  4. Don't use gas appliances again until they've been checked.

    Illustration of a gas engineer kneeling to check the back of a cooker with a small tool
    Illustration

    Cornwall Fire and Rescue Service says not to use gas appliances until the engineer has checked them.

Bottled gas (LPG cylinder)

  1. Shut the leak off at the cylinder, then open doors and windows.

    Illustration of a hand turning the valve on top of a gas cylinder in a kitchen, with the window open
    Illustration

    PSO's LPG safety sheet says: don't panic, shut down the leak from the source, and open all doors and windows. Never switch anything on, not even the lights or the exhaust fan in the dark (PSO).

  2. Never try to repair a leaking cylinder.

    Illustration of a gas cylinder standing by an open door while the woman, outside, makes a phone call
    Illustration

    PSO: leaking cylinders must never be repaired by the user. Leave and call your supplier, or Rescue 1122 if there is any danger (Rescue 1122).

Know the signs, and stop it happening

  1. Learn the other signs of a leak, not just the smell.

    Illustration of a lawn with a patch of dead grass, sound lines rising from it, and a puddle with bubbles beside it
    Illustration

    The California Public Utilities Commission lists a hissing or roaring sound, bubbles in standing water, unexplained dead plants, dirt or water blowing into the air, and a damaged connection to a gas appliance.

  2. Fit a gas detector, and a carbon monoxide alarm.

    Illustration of a small round detector on a hallway wall next to a bedroom door
    Illustration

    New York City now requires natural gas detectors in homes with gas piping, within 15 feet of the main entrance to each bedroom (NYC311). A gas detector doesn't detect carbon monoxide, which has no smell (VdF NRW), so you also need a CO alarm.

  3. Turn gas heaters off before you sleep.

    Illustration of a woman in pyjamas turning off a gas room heater beside her bed, with the window slightly open
    Illustration

    Rescue 1122 says never to use a gas heater while sleeping, and to keep a window or vent partly open while it runs (Rescue 1122).

What each country says

UKGermanyUSPakistan
FirstOpen windows; gas off at the meter, unless it's in a cellar (SGN)Open windows; close the main shut-off valve (Feuerwehr Lehrte)Leave on foot first; don't turn valves (CPUC)Shut the gas off, open windows, move outside (Rescue 1122)
NeverSwitches, flames, smoking (SGN)Switches, doorbells, a phone in the danger area (Feuerwehr Lehrte)Phones, switches, garage door openers, vehicles (CPUC)Lights or exhaust fan, even in the dark (PSO); matches, lighters, switches (Rescue 1122)
Call0800 111 999, free; 999 in an emergency (SGN, Cornwall FRS)112 and your gas supplier (Feuerwehr Lehrte)911, then your gas company (NYC311, CPUC)SNGPL 1199 (APP); Rescue 1122

How to tell it's sorted

  • Everyone got out without anyone touching a switch or making a flame.
  • You called from outside, and the gas service or fire brigade came.
  • An engineer has checked your appliances before you use them (Cornwall Fire and Rescue Service).
  • You can no longer smell gas anywhere in the home.

If something isn't right

What happensWhat it meansWhat to do
The smell comes back after the engineer has leftThe leak may not be fixedStart again: no switches, open windows, get out and call
A hissing or roaring soundA bigger leak (CPUC)Leave straight away and call from a distance
The smell is outside, in the streetThe leak may be in a pipe outsideLeave the area on foot and call (CPUC)
Headache, dizziness or feeling sick, but no gas smellPossible carbon monoxide (NHS)Get into fresh air; in the UK call 111, or 999 if severe (NHS)

Keep your gas emergency number with your home emergency kit list.

Questions readers ask

Is it free to call the gas emergency number in the UK?

Yes. SGN describes 0800 111 999 as a free 24-hour helpline, and Cornwall Fire and Rescue Service says it runs day and night, every day of the year.

Why does gas smell of rotten eggs?

Gas suppliers add an odorant that gives natural gas a clear warning smell, similar to rotten eggs (Freiwillige Feuerwehr Lehrte, California Public Utilities Commission).

What if my gas meter is in the cellar?

Don't go down to it. SGN and Cornwall Fire and Rescue Service both say not to enter a cellar or basement, even to reach the meter. If the smell is in the cellar, leave the building (Cornwall Fire and Rescue Service).

Can I use my mobile phone?

Not inside or near the smell. German fire brigades and the California Public Utilities Commission both say not to use a phone in the area where the gas is. Call once you're outside and away from it.

Could I have a gas problem I can't smell?

Yes: carbon monoxide from a faulty boiler, cooker or heater has no smell at all (VdF NRW). Only a carbon monoxide alarm warns you. Headache, dizziness and feeling sick can be signs (NHS).

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