Regulations & Safety
Are Interlinked Smoke Alarms a Legal Requirement?
In England, interlinked alarms are required for new builds and rewires, and at least one alarm per storey is required in rented homes. Here is the detail.
By Steels Electrical · 4 June 2026 · 4 min read
The short answer
In England, interlinked smoke alarms are required by Building Regulations for new builds and whenever you rewire or carry out relevant electrical work. In rented homes, at least one smoke alarm is required on every storey (and a CO alarm in rooms with a fixed combustion appliance), though these need not be interlinked. For existing owner-occupied homes there is no retrospective duty to interlink — but it is strongly recommended. (Note: Scotland’s rules are stricter and require interlinked alarms in all homes.)
Interlinking means when one alarm detects smoke, they all sound — which buys vital extra seconds, especially at night. The legal position in England depends on the type of property and whether you are doing electrical work.
When interlinking is required in England
Under Building Regulations (Approved Document B), interlinked, mains-powered alarms are required when:
- You build a new home.
- You rewire a property or carry out other notifiable electrical work that triggers the requirement.
- You materially alter the property in a way that brings the standard into play.
Rented homes
Separate rules require landlords in England to provide at least one smoke alarm per storey and a carbon monoxide alarm in any room with a fixed combustion appliance, and to make sure they work at the start of each tenancy. These do not have to be interlinked — but interlinked mains alarms are the gold standard and what we recommend fitting.
Frequently asked questions
- Do I have to interlink alarms in my own home?
- Not retrospectively in England, unless you are rewiring or doing relevant work. But interlinked alarms dramatically improve warning time, so they are well worth fitting voluntarily.
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- Do I Need Building Control Sign-Off for Rewiring? Yes — a rewire is notifiable under Part P. A registered electrician self-certifies and notifies building control for you. Here is how it works.