Updated for the 1 May 2026 law change: Renters' Rights Act 2025 now in force
Reviewed for the Renters' Rights Act · Updated 20 July 2026

Smoke and carbon monoxide alarms: the landlord's rules

The Smoke and Carbon Monoxide Alarm Regulations set some of the cheapest compliance duties in landlording, and among the most enforced. The requirements:

What must be installed

The two ongoing duties

Alarms must be shown to be working at the start of each tenancy: test them at check-in and record it on the inventory with the tenant's signature. During the tenancy, when a tenant reports a faulty alarm, the landlord must repair or replace it as soon as reasonably practicable. Day-to-day battery changes sit with tenants as ordinary tenant-like use, which a good agreement states explicitly.

Enforcement

Local authorities can fine up to £5,000 per breach, and missing alarms undermine everything else: they appear in the How to Rent guide the tenant holds, feature in the compliance checklist, and look terrible in any possession claim or fire investigation. Mains-wired or sealed ten-year units cost little and remove the battery argument entirely.

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Frequently asked questions

Who is responsible for testing smoke alarms in a rental?

The landlord must ensure they work at the start of the tenancy; routine testing and battery replacement during the tenancy falls to the tenant, with the landlord repairing or replacing faulty units on report.

Do I need a CO alarm with a gas cooker only?

No. Gas cookers are excluded; the CO duty attaches to fixed combustion appliances such as boilers, gas fires and wood burners.