What is a legionella certificate?
Updated 12 September 2026
Short answer
There is no such thing as an official "legionella certificate" in UK law. The term is shorthand for the written legionella risk assessment that the duty holder must produce under ACOP L8. Letting agents, CQC inspectors, and procurement teams often ask for one, and what they want is a copy of your written assessment.
The phrase "legionella certificate" has become common shorthand in the letting and property industry, but it does not correspond to any specific document defined in law. The legal requirement is for a written risk assessment, not a certificate of any kind.
What people usually mean
When someone asks for a "legionella certificate", they generally mean one of three things:
- A copy of the written risk assessment. This is the most common request and the one that the duty holder is legally required to be able to produce.
- A certificate of analysis from a sampling programme. This is issued by the UKAS-accredited laboratory after it has processed a water sample. It is evidence of the sample result, not of compliance.
- A certificate of disinfection. This is issued after a system has been cleaned and chemically or thermally disinfected, usually by the contractor who did the work. It documents the procedure and the post-disinfection sample results.
What you should supply
If the request is from a letting agent or a routine compliance check, give them a copy of the written risk assessment, signed and dated, with the name of the assessor and the date of the next scheduled review. That is the document that demonstrates compliance with ACOP L8.
If the request is from a contractor quoting for follow-on work, they may want the risk assessment plus the most recent monitoring records to understand what state the system is in.
Third-party certification schemes
Some commercial schemes issue certificates to companies or individuals who have completed their training. These are not regulatory certificates and do not confer a legal status. They can be useful evidence of competence but they are not required by ACOP L8.
Legal basis
ACOP L8 paragraphs 68 to 72 on records. HSG274 Part 2 section 2.7 on documentation.
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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.
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