If you can smell gas at home, act now and do not wait to see if it fades. Do not touch any electrical switch, light anything, or use your phone inside the house. Open doors and windows, turn the gas off at the meter only if safe, get everyone out, and call the National Gas Emergency Service on 0800 111 999 from outside. The call is free, 24 hours a day. Do not go back inside, or turn the gas back on, until an engineer has given you the all-clear.
Find your situation first
- Strong smell, or getting stronger: leave now and call 0800 111 999 from outside.
- Faint smell that stays faint: open doors and windows, turn the gas off at the meter if safe, leave, and call 0800 111 999.
- Someone feels unwell: get everyone into fresh air.
- You can smell gas outside: move away and call 0800 111 999.
- Carbon monoxide alarm sounding, no gas smell: carbon monoxide has no smell. See gas smell or carbon monoxide.
What does gas smell like — and what else gives it away?
Natural gas has no smell of its own. Suppliers add a chemical called mercaptan so a leak can be detected, and it smells like rotten eggs, rotten cabbage, or old socks. If you notice that smell near a cooker or boiler, treat it as a leak.
The smell is the most common warning, but not the only one:
- A hissing or whistling sound near gas pipework or an appliance.
- Bubbles in standing water near a pipe.
- Houseplants dying for no clear reason near a gas appliance.
- A gas bill that jumps for no clear reason.
- A gas detector alarm sounding. A gas detector is a different device from a carbon monoxide alarm.
Do not rely on the smell alone: some people cannot smell mercaptan well, and a small leak in a ventilated room may be faint. If something feels wrong, call 0800 111 999. A wasted call costs nothing.
Where does the smell usually come from?
Most household gas leaks come from a small number of places.
| Where the leak is | What you will notice | Who fixes it |
|---|---|---|
| Loose or worn cooker hose | Smell near the cooker, often after it has been moved | Gas Safe engineer only |
| Faulty joint on a boiler or gas fire | Smell near the appliance, sometimes with a faint hiss | Gas Safe engineer only |
| Corroded gas pipework | Smell along a pipe run, often in a damp cellar | Gas Safe engineer |
| Connection at the gas meter | Smell at the meter or in the meter cupboard | Emergency service, then a Gas Safe engineer |
| A burner left on with no flame | Strong smell in the kitchen, hob knob on but no flame | Safe check: turn the knob off and call 0800 111 999 |
| Pilot light gone out | Smell near an older boiler or gas fire | Do not relight it: leave and call 0800 111 999 |
| Damaged external pipe or meter box | Smell outside, near the meter box | Emergency service: call 0800 111 999 |
A burner left on is the one case where you can stop the gas yourself. Every other row needs an engineer. Never tighten a gas fitting, use tape or sealant on a gas joint, or open the boiler casing. Gas work is for a Gas Safe registered engineer only, and working on gas without the right registration is illegal.
What to do now, step by step
Work through these in order.
- Do not touch any electrical switch, on or off. Light switches, sockets, the boiler controls, and the doorbell can all make a tiny spark.
- Put out naked flames. No cigarettes, matches, lighters, or candles, and do not light the hob to test it.
- Open doors and windows. Let the gas out and fresh air in.
- Turn off the gas at the meter, only if you can reach it safely. The emergency control valve is next to the gas meter: turn the handle a quarter-turn, so it sits across the pipe. If your meter is in a cellar or basement and you can smell gas there, do not go in. Leave and call from outside.
- Get everyone out. Take children and pets with you. If the smell is strong or getting stronger, do not wait to turn off the gas first.
- Call 0800 111 999 from outside. This is the National Gas Emergency Service, free, 24 hours a day. Call from a safe distance, not from inside the house, and follow the operator’s advice.
- Tell your neighbours. Gas can travel through shared walls. Knock and tell them.
- Wait outside for the emergency engineer. They will make the property safe and cap the leak if needed. Do not go back in until they say it is safe.
- Do not turn the gas back on yourself. Only a Gas Safe registered engineer can turn the supply back on, after the repair and safety tests.
If you feel unwell — headache, dizziness, nausea, or shortness of breath — get into fresh air first. Call NHS 111 for advice, or 999 if someone has difficulty breathing, sudden confusion, loss of consciousness, or chest pain.
What not to do
- Do not use your mobile phone inside the house: a phone can spark.
- Do not switch anything on or off.
- Do not smoke or light any flame anywhere near the property.
- Do not try to find or fix the leak yourself.
- Do not relight a pilot light or burner until an engineer has checked it.
- Do not go back inside until the emergency engineer or a Gas Safe engineer has given you the all-clear.
Who does what after you call
People often expect one visit to fix everything. Two different people do two different jobs.
| Who | What they do | What they do not do | Who pays |
|---|---|---|---|
| National Gas Emergency Service (0800 111 999) | Finds the leak, makes the property safe, and caps the pipe if needed | Does not repair appliances or pipework | Free |
| Gas Safe registered engineer | Finds and repairs the fault, tests the system, and turns the gas back on | Cannot turn the gas back on until tested | You pay, unless your landlord or insurer covers it |
| Your landlord (if you rent) | Must arrange the repair and the annual check, and give you the CP12 | Does not attend the emergency call-out | The landlord pays for work on their appliances |
| Your gas supplier | Owns the meter and the pipework up to it | Does not repair pipework in your home | Their side of the meter is their responsibility |
So the sequence is: call 0800 111 999 first, let the emergency engineer make the property safe, then book a Gas Safe registered engineer to repair the fault. If you rent, tell your landlord as soon as the property is safe. The Gas Safe Register’s official list of registered engineers lets you check any engineer before they start work.
Gas smell or carbon monoxide — they are not the same
A gas leak smells of rotten eggs because mercaptan is added to the gas. Carbon monoxide has no smell, no colour, and no taste, and you cannot detect it without an alarm.
So a gas smell means a gas leak: ventilate, leave, and call 0800 111 999. No gas smell does not mean no danger: a faulty boiler can produce carbon monoxide silently, and the warning signs are headaches, dizziness, and nausea that ease when you leave the house. Our guide to carbon monoxide signs and symptoms explains the warning signs and where to put an alarm. Fit an audible carbon monoxide alarm and test it regularly.
What if you smell gas outside?
Move away from the smell. Once you are at a safe distance, call 0800 111 999 and report it. The emergency service covers leaks outside too. Tell your neighbours to check for a smell indoors. Do not try to find the source, and do not open a meter box or lift a pavement cover.
If your home runs on LPG from a bulk tank or cylinders, the 0800 111 999 line covers mains gas emergencies. For an LPG leak, leave the property, keep away from the tank, and call your LPG supplier’s emergency number.
When to stop and call
With a gas smell, call 0800 111 999 first, then call a plumber. Do not wait to see if the smell fades, and do not use the appliance again until an engineer has checked it. Call a Gas Safe engineer if the emergency engineer has capped the leak and the repair still needs doing, or if the smell keeps coming back after a repair.
Once the property has been made safe, contact our gas plumber in Bradford service, or call 01274 041977. Tell us what the emergency engineer capped, and which appliance the smell came from. A Gas Safe registered engineer can then trace the fault and repair it before the gas goes back on. For the yearly check that catches worn joints before they leak, our boiler service in Bradford covers the boiler.
What does a gas leak repair cost?
The emergency visit is free; the repair afterwards is chargeable. The figures below are UK guide averages from Checkatrade’s gas leak repair cost guide, updated June 2026, not this business’s prices.
| Job | UK guide average | Notes |
|---|---|---|
| Gas leak repair (labour) | Average £200 | Most repairs take 1 to 3 hours |
| Gas pipe repair (labour and materials) | £77 to £920, average £380 | Simple joint repair at the low end; hidden pipe at the high end |
| Emergency call-out | Costs more | Evening, weekend, or bank holiday |
| Emergency attendance by the National Gas Emergency Service | Free | Making the property safe costs nothing |
Do not compare quotes while gas is leaking: get everyone out, call 0800 111 999, and arrange repairs once the risk has been made safe. Get a written quote before work starts, and ask what it covers.
Why this matters more in Bradford homes
Bradford’s housing makes a gas smell more urgent in three ways. First, the terraces and back-to-backs share walls, floors, and sometimes cellars, so gas from one home can reach the next. Second, many homes have the gas meter in a cellar or under the stairs, which is exactly where you should not go if you smell gas there. Leave and call from outside instead. Third, older pipework and older boilers are common, and a joint that has sat untouched for decades is more likely to weep than a new one.
Rented terraces add another layer: tenants may not know where the meter is, or that the landlord must provide an annual CP12 certificate. If you rent in Bradford and have never seen your CP12, ask your landlord for it. Knowing where your meter and valve are today costs nothing: find them now, while there is no smell.
Preventing the next scare
- Book an annual boiler service with a Gas Safe registered engineer.
- Fit a carbon monoxide alarm in every room with a gas appliance, and test it regularly.
- Consider a gas detector alarm as well: it detects leaking gas.
- Find your gas meter and emergency control valve today.
- Never move a gas cooker yourself to clean behind it.
- Keep records of servicing, and check your landlord’s CP12 if you rent.
Frequently asked questions
What number do I call if I smell gas?
Call the National Gas Emergency Service on 0800 111 999. The call is free and the line is staffed 24 hours a day. Call from outside the property.
Should I turn off my gas at the meter if I smell gas?
Yes, if you can reach it safely: turn the emergency control handle a quarter-turn so it sits across the pipe. If your meter is in a cellar or basement and you can smell gas there, do not go in. Never turn the gas back on yourself.
Is it safe to stay in the house if I smell gas?
If the smell is strong or getting stronger, leave straight away and call from outside. For a faint smell, open doors and windows, turn the gas off if safe, leave, and call 0800 111 999 for advice. Do not go back inside until an engineer has given you the all-clear.
Does the emergency gas engineer fix the leak?
The emergency engineer makes the property safe and caps the leak if needed, and that visit is free. Repairing the appliance or pipework is a separate job for a Gas Safe registered engineer, which you pay for.
How much does a gas leak repair cost?
Checkatrade guide averages, June 2026: gas leak repair labour averages £200; gas pipe repair £77 to £920, averaging £380. Most repairs take 1 to 3 hours. Emergency call-outs cost more. The emergency attendance itself is free.
What if I smell gas but my carbon monoxide alarm is silent?
That is normal: a carbon monoxide alarm only detects carbon monoxide, which has no smell. A gas leak smells of rotten eggs because mercaptan is added to the gas. A silent alarm does not mean there is no gas leak, so call 0800 111 999 anyway.
Plumber Bradford Pros, 164 Dyson Street, Bradford BD9 4DE. Call 01274 041977 for help with gas plumbing in Bradford.
