Do I need a legionella risk assessment?
Updated 16 August 2026
Short answer
Almost certainly yes, if you are an employer, a landlord, or in control of any non-domestic premises. The Health and Safety at Work Act 1974 makes the duty universal, and ACOP L8 requires a written assessment. The only real question is how detailed the assessment needs to be, which depends on how complex your water system is and who is exposed to it.
There is a widespread misconception that legionella assessments are only needed for hospitals and large commercial buildings. They are not. The duty to assess applies to any non-domestic water system, from the smallest rented flat to the largest hospital estate. What changes between those two extremes is the depth of the assessment and the detail of the control scheme, not whether an assessment is required at all.
If you rent out residential property
Yes. A tenancy makes your property a workplace for you as the landlord under section 3(2) of the Health and Safety at Work Act 1974. For a typical single let with a combi boiler and no stored water, the assessment may be half a page long and the control scheme may amount to advising the tenant to run unused taps weekly. That is still an assessment, and it needs to be written down.
If you employ people
Yes. Any premises with employees falls within section 2 of the Act, and the water system falls within the scope of the general duty to protect their health. Even a shop with a single toilet and a kettle has a water system that needs to be assessed, though the assessment will be short.
If you run a care home, hospital, school, or hotel
Yes, and the assessment is a much more substantial document. These building types combine larger water systems with more vulnerable occupants, and the regulatory expectation is for a full survey covering every outlet, detailed control schedules, and monthly or quarterly monitoring.
If you have a cooling tower or spa pool
Yes, and the scope broadens further. Cooling towers are notifiable to the local authority under the 1992 Regulations, and both cooling towers and spa pools have their own technical guidance in HSG274 Parts 1 and 3 respectively.
If you own a second home you let occasionally
Yes. A holiday let is a workplace for you as the operator. The risk profile is usually low for small properties with a modern system, but the duty applies the same way.
If the property is your own home and nobody else uses it
No. The Act does not apply to purely domestic premises occupied only by the people who own them. As soon as you let any part of the property, or you employ someone to work there (a cleaner, a carer), the position changes.
How to get started
For most simple premises, a written assessment does not require a contractor. You can use our free template and the guidance in HSG274 Part 2 to carry out the assessment yourself. For care homes, hospitals, leisure facilities, premises with cooling towers, and any premises where the occupants are vulnerable, you should engage an LCA-registered contractor.
Legal basis
Health and Safety at Work Act 1974 sections 2 and 3. ACOP L8 paragraphs 40 to 52 on the assessment requirement. HSG274 Part 2 paragraphs 2.1 to 2.29 on the assessment process.
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Free legionella risk assessment template
A structured Word document following the five-step approach in ACOP L8. Covers risk identification, written scheme, monitoring, and records. If it isn't written down, you can't evidence it.
Follows ACoP L8 and HSG274 Part 2. Free. No spam.