Legionella risk assessment
A written assessment of water-system risk in a let property.
2 min read · Updated 2 August 2026
Overview
Landlords have a duty under health and safety law to assess and control the risk of legionella bacteria in the water system. For most small domestic properties this is a simple written assessment reviewed periodically, covering stored water, dead legs, temperatures and showerheads.
Legal requirements
- The duty arises under the Health and Safety at Work etc. Act 1974 and the COSHH regulations.
- No certificate is legally required, but a written assessment must be available on request.
Practical guidance
- Tell tenants to run taps and showers after any period of vacancy and to descale showerheads.
This wiki entry is general information for UK landlords and letting agents, not legal advice. Rules differ across England, Wales, Scotland and Northern Ireland — check your local requirements or take advice before acting.