Guide
Landlord legionella risk assessment: legal duties and 2026 cost
Updated
The landlord duty is real, but smaller than the sales patter suggests. Here is what the Health and Safety at Work etc. Act 1974 and ACOP L8 actually require of a domestic landlord, and what it should cost.
The duty, precisely
Landlords who provide residential accommodation have a duty to assess and control the risk of exposure to legionella bacteria, as persons in control of premises under section 3(2) of the Health and Safety at Work etc. Act 1974, with the Control of Substances Hazardous to Health Regulations 2002 applying to the risk itself. The HSE's guidance for landlords states the duty directly (HSE, landlords' responsibilities). This applies to ordinary domestic lets, not just HMOs.
What compliance actually looks like
- A risk assessment of the hot and cold water system: tanks, cylinders, dead legs, little-used outlets, temperatures. For a typical domestic property with a combi boiler and mains-fed cold water, HSE describes the risk as low.
- Simple control measures where the assessment finds risk: keeping hot water hot, cold water cold, flushing outlets after void periods, removing redundant pipework.
- Telling tenants about any control measures they should maintain, such as cleaning shower heads.
- Review when the system or its use changes, see how often assessments are needed.
What it costs, and the certificate myth
A professional assessment of a single rented house or flat typically costs £60–£150 (typical 2026 quotes; portfolio landlords pay less per property). Be aware of two common upsells: there is no such thing as a legionella certificate required by law, and HSE states that legionella testing of domestic hot and cold water systems is not usually required. A landlord who is competent to do so may carry out the assessment themselves; many prefer a professional record for their file, which is a reasonable choice, not a legal necessity.
Getting it done proportionately
- Check what you have: combi boiler and mains cold water is the low-risk case; stored water, tanks and long-vacant properties deserve more care.
- Commission or carry out the assessment and keep the written record with your gas safety and EICR paperwork.
- Act on the findings and brief the tenant, the control measures for domestic systems are cheap and mostly behavioural.
Letting agents sometimes present a legionella certificate as a legal precondition of letting. It is not; the legal duty is the risk assessment and any controls it identifies. The HSE landlord page is the authoritative reference (hse.gov.uk).