Smoke and carbon monoxide alarms: what landlords must fit
How many alarms each storey needs, which rooms require a CO alarm, who tests what and when, where the devices should physically go — and the £5,000 penalty behind a remedial notice.
The rules in England
- Smoke alarms: at least one on every storey used as living accommodation.
- CO alarms: one in every room used as living accommodation that contains a fixed combustion appliance, excluding gas cookers.
- Working on day one: every required alarm must be proven in working order at the start of each new tenancy.
- Repair duty: once a tenant reports a fault, repair or replace as soon as reasonably practicable.
The 2022 amendment extended CO alarms from solid-fuel-only to all fixed combustion appliances and added the explicit repair duty. It applies to social as well as private landlords.
Scotland, Wales and Northern Ireland
Scotland requires interlinked alarms in every home: a smoke alarm in the main living room, one in each circulation space per storey, a heat alarm in the kitchen, and a CO alarm wherever there is a carbon-fuelled appliance or flue.
Wales requires mains-wired interlinked smoke alarms on each storey plus CO alarms in rooms with fuel-burning appliances, as part of the fitness for human habitation standard under the Renting Homes (Wales) Act.
Northern Ireland applies its own building control and HMO standards rather than the 2015 England regulations.
Where to put them
- Smoke alarms: ceiling-mounted in circulation spaces, at least 300mm from walls and light fittings.
- Avoid kitchens and bathrooms for optical smoke alarms — use a heat alarm in the kitchen instead.
- CO alarms: one to three metres horizontally from the appliance, at head height, or exactly as the manufacturer specifies.
- Never inside a cupboard, behind a door, or in a dead air space at the apex of a sloped ceiling.
Evidencing compliance
- Test every alarm with the tenant present on the first day of the tenancy.
- Record room, alarm type, expiry date printed on the unit and the test result.
- Have both parties sign the record; add photographs of each device in place.
- Log the alarm expiry dates as renewal reminders — ten years for smoke, five to seven for CO.
- Keep a dated record of any fault reported and the date it was remedied.
Alarms sit in the same evidence pack as the annual gas check, the EICR and the EPC. The full renewal cycle is in our compliance checklist.
Penalties for getting it wrong
Where a local authority has reasonable grounds to believe the duty is breached, it serves a remedial notice giving 28 days to comply. If the work is not done, the authority can arrange it and impose a penalty charge of up to £5,000. A missing or untested alarm also weakens an insurance position and can be material in any claim following a fire or CO incident.
Frequently asked questions
How many smoke alarms does a rented property need?
At least one smoke alarm on every storey of the property that is used as living accommodation. A two-storey house needs a minimum of two; a bungalow needs one. Bathrooms and lavatories count as living accommodation for this purpose, so a storey containing only a bathroom still needs an alarm.
Where are carbon monoxide alarms required?
In England, a CO alarm is required in any room used as living accommodation that contains a fixed combustion appliance — gas boiler, gas fire, wood burner, oil boiler or solid fuel appliance. Gas cookers are excluded from the requirement, though fitting one anyway is sensible.
When must the alarms be tested?
The landlord must ensure every required alarm is in working order on the first day of each new tenancy. Testing at the start of the tenancy, with the tenant present and the check recorded and signed, is the practical way to evidence it.
Who is responsible for testing during the tenancy?
The tenant is expected to test alarms routinely and report faults. Once a fault is reported, the landlord must repair or replace the alarm as soon as reasonably practicable — the 2022 amendment made that repair duty explicit.
Do the alarms need to be mains-wired?
Not in England: the regulations do not specify a type, so battery, sealed long-life or mains-wired alarms all satisfy the rule. Sealed ten-year alarms remove the tenant-removes-the-battery problem. Building regulations may require mains-wired interlinked alarms in new build or major refurbishment, and licensing conditions can go further.
What is the penalty for missing alarms?
The local authority serves a remedial notice giving 28 days to comply. If the landlord does not, the authority can arrange the work and impose a penalty charge of up to £5,000.
What is the rule in Scotland?
Scotland requires interlinked alarms in every home: one smoke alarm in the main living room, one in every circulation space on each storey such as hallways and landings, a heat alarm in the kitchen, and a CO alarm where there is a carbon-fuelled appliance or a flue. Interlinking means when one sounds, they all sound.
What about Wales and Northern Ireland?
Wales requires mains-wired interlinked smoke alarms on each storey and CO alarms in rooms with fuel-burning appliances, under the Renting Homes (Wales) fitness standards. Northern Ireland applies its own building control and HMO requirements. Check the devolved rules for properties outside England.
Do HMOs have stricter alarm requirements?
Yes in practice. Licensed HMOs are subject to licence conditions and a fire risk assessment, which typically require a grade D or grade A interlinked system, emergency lighting in some layouts and fire doors. The 2015 regulations are the floor, not the ceiling.
How long do alarms last?
Most smoke alarms have a design life of ten years and CO alarms typically five to seven, both marked on the unit. Replace on the marked expiry date rather than waiting for a failure, and record the replacement against the property.
Where should alarms be positioned?
Smoke alarms are best fixed to the ceiling in a circulation space, at least 300mm from any wall or light fitting. CO alarms go one to three metres horizontally from the appliance, at head height or as the manufacturer specifies. Follow the manufacturer's instructions — they are what an inspector will compare the installation against.
How do I prove the alarms worked at check-in?
Record the test in the inventory or a dedicated alarm test sheet: date, room, alarm type, result, and signatures from both parties, with photographs. Store it against the property alongside the gas certificate and EICR so the whole compliance pack is retrievable in one go.
Sources and citations
Every figure, deadline and penalty on this page is drawn from primary UK legislation and official government guidance. Last reviewed against these sources in August 2026.
- [1]The Smoke and Carbon Monoxide Alarm (England) Regulations 2015 — legislation.gov.ukAlarm requirements, the test-on-day-one duty and the remedial notice regime.
- [2]The Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022 — legislation.gov.ukExtends CO alarms to every room with a fixed combustion appliance and adds the repair duty.
- [3]Smoke and carbon monoxide alarms: explanatory booklet for landlords — GOV.UKOfficial guidance, including the £5,000 maximum penalty charge.
- [4]Fire and smoke alarms in Scottish homes — Scottish GovernmentInterlinked alarm standard applying to all Scottish homes.
About the publisher
This page is published by NestIQ Wealth, a UK property management and compliance platform used by self-managing landlords to track statutory deadlines, store certificates with full version history, and evidence compliance per property. Our guidance is written by the team that builds those compliance rules into the product, so the dates, cycles and penalties here are the same ones the software enforces.
- •Researched from primary sources. Every rule is checked against legislation.gov.uk, GOV.UK guidance and the responsible regulator — never rewritten from other blogs. See how we source our data.
- •Reviewed as the law changes. Pages carry a visible review date — last reviewed August 2026 and are revisited when legislation, deadlines or penalty levels move.
- •No hidden commission. We are not paid to refer you to contractors, brokers or agents. Costs quoted are illustrative market ranges, not quotes or offers.
- •Guidance, not regulated advice. Nothing here is legal, tax or financial advice. For decisions specific to your circumstances, speak to a solicitor, accountant or qualified adviser.
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Log every alarm test against the property
NestIQ Wealth keeps the check-in alarm record, device expiry dates and fault history per property, and reminds you before anything lapses.
Start freeThis guide is general information for UK landlords, correct to the best of our knowledge at the time of writing. It is guidance only — not financial, tax or legal advice. Check the current legislation, or take professional advice, before acting.