Legionella assessment review follows validity, not a certificate label
The useful question is whether the assessment still describes the water system, its use and the controls in place. HSE's Approved Code of Practice L8 provides the framework for identifying and controlling legionella risk. HSE's assessment guidance requires review when there is reason to think the assessment is no longer valid, alongside regular review.
This approach avoids opposite mistakes. An owner may assume an assessment remains adequate because the document appears current, despite substantial alterations. Another may buy a replacement document without checking whether its earlier actions were ever completed. Neither approach answers whether the written assessment matches the installation now in service.
If you need help interpreting an existing document, send it with your legionella risk assessment enquiry. Include information about alterations and unresolved findings. For rented homes, the landlord legionella assessment guide explains the initial assessment separately from the review question.
HSE reasons for reviewing a legionella assessment
HSE's assessment guidance, read with L8, identifies circumstances that can make a review necessary: changes to the water system or its use, changes to the building's use, new risk or control information, checks showing controls are ineffective, changes to key personnel, and a case associated with the system. These are reasons to examine validity, rather than a replacement timetable.
For example, a plant alteration can leave the old schematic inaccurate. A different occupation pattern can change which outlets receive use. A change in the person managing controls can leave tasks without an owner. Describe the event and its implications to the competent person reviewing the assessment, instead of merely requesting a new date on the cover.
Do not wait for a planned document review to report evidence of a failed control. HSE's assessment guidance includes ineffective controls among reasons for review. Keep the finding, investigation and resulting changes together so that the updated assessment has a traceable basis.
Legionella review evidence from the working system
As a practical way to prepare for review, collect the current assessment, system description, available monitoring records and repair information. Add a short account of how the building is occupied. Where a record is missing, identify the gap explicitly; do not replace it with a statement that everything has remained satisfactory.
Compare the existing document with what is physically present. Are named tanks, heaters and outlets still there? Have abandoned branches been removed or merely disconnected from use? Does the drawing show a new bathroom? These checks organise the evidence for a reviewer. They do not establish a separate legal inspection interval.
Make the outcome readable. A review record can identify what information was checked, what changed, what remains uncertain and which actions follow. Keep previous versions available so someone investigating an alteration can understand why the current controls differ. Where specialist advice is needed, pass on the underlying findings rather than only the last report's conclusion.
Domestic legionella review and changes between tenancies
HSE's landlord guidance says assessments should be reviewed periodically in case anything changes. It also notes that, where occupied properties are difficult to access, appropriate checks can be made during other visits, such as maintenance. This is practical advice about access, not a statement that every maintenance visit requires a replacement assessment.
The same HSE landlord guidance calls for careful management where properties remain vacant. A tenancy handover is therefore useful context to give the reviewer: explain the vacancy, any plumbing work and whether the prior description of normal use still applies. Do not invent a universal renewal obligation attached to each new tenancy.
The landlord compliance checklist can help organise property information across different services. Keep the reasoning for each service separate, because a convenient combined administration date does not establish the review requirement for the water system.
Commissioning a legionella assessment review with a clear scope
Tell the assessor why you are seeking a review. A changed plant room, unexplained monitoring result and routine validity check are different instructions. Identify the responsible contact and arrange access to the relevant system. Ask the assessor to explain whether existing information can be retained and where fresh investigation is needed.
Agree the deliverable before appointing legionella risk assessment support. Request clear findings about the current assessment's adequacy and any revisions, rather than an unexplained expiry statement. For buildings with several management parties, our facilities manager support can help coordinate the enquiry; provide the water-system responsibilities and action owners so the review addresses the correct areas.
About our Legionella Risk Assessments service
For the service itself, see Legionella Risk Assessments.