When should a Legionnaires risk assessment be reviewed?
A Legionnaires’ risk assessment should be reviewed regularly and whenever there is a significant change to the water system, its use, management or occupancy. It should also be revisited after an incident or suspected case of Legionnaires’ disease, or when monitoring, maintenance or other evidence indicates that existing control measures may no longer be effective.
There is no single review date that is suitable for every water system. The review frequency should be based on the level of risk, the complexity of the system and the strength of the control arrangements. The responsible person should define a planned review cycle in the organisation’s water safety procedures, while ensuring that the assessment remains current whenever circumstances make the original conclusions unreliable.
UK health and safety guidance, including the HSE’s Approved Code of Practice L8 and associated guidance on the control of legionella bacteria, expects risk assessments to be kept under review. The assessment is not a one-off compliance document. It should continue to reflect the actual system, how it is operated and maintained, and the people who may be exposed to contaminated aerosols.
A scheduled review should examine whether the assessment still describes:
- all hot and cold-water systems, outlets, storage vessels, tanks, calorifiers and other relevant equipment;
- the way water is generated, stored, distributed, used and discarded;
- the responsibilities assigned to the responsible person, contractors and operational staff;
- the control measures set out in the written scheme;
- the monitoring, inspection, cleaning, disinfection and maintenance arrangements; and
- the groups of people who could be especially vulnerable to Legionnaires’ disease.
Reviewing the document should involve more than checking its date. The assessor or competent reviewer should compare the written information with the system in operation. This may include inspecting plant rooms and outlets, checking schematic drawings, discussing operating practices with relevant staff, examining temperature and flushing records, and reviewing maintenance or remedial-work reports. If the assessment relies on information that cannot be verified, its conclusions may need to be revised.
The review should also consider whether control measures are proportionate and effective. For example, a procedure may exist for monitoring sentinel outlets, but the assessment should establish whether the outlets selected are appropriate, whether readings are taken consistently, whether exceptions are investigated and whether corrective actions are completed. Repeated missed checks, unexplained temperature results, incomplete records or recurring remedial actions can indicate that the documented arrangements need to be reassessed.
A review is particularly important where the use or occupancy of a building has altered. Changes such as reduced occupancy, periods of vacant accommodation, increased use of showers, the introduction of healthcare or care-related activities, or the presence of more susceptible individuals can affect exposure and water demand. These factors may alter stagnation risks and the level of control required, even where the physical pipework has not changed.
The review process should produce a clear written outcome. This should record:
- the date and scope of the review;
- who carried it out and their competence;
- the information and records examined;
- any changes to the water system, building use or responsibilities;
- revised findings and control measures;
- actions required, with ownership and target dates; and
- the date or circumstances for the next planned review.
A review does not automatically mean that a completely new assessment is required. If the system, risks and controls remain accurately represented, a documented review may confirm that the existing assessment remains valid. However, substantial changes, gaps in evidence or altered risk factors may require a fresh assessment rather than a minor amendment. The decision and its reasoning should be recorded so that it can be understood during an internal audit, inspection or investigation.
The responsible person remains accountable for ensuring that the assessment is reviewed and acted upon, even when a specialist contractor carries out the work. External expertise can provide an independent assessment of system risks, but it does not transfer the organisation’s management responsibilities. Findings should therefore be incorporated into the written scheme, staff instructions, monitoring arrangements and maintenance planning where appropriate.
Blue Fish Water Management Ltd can support organisations with legionella risk assessments, water system reviews, compliance audits, monitoring and remedial advice. Any review should be tailored to the system concerned and supported by current evidence rather than treated as a routine document-renewal exercise.
A review of a Legionnaires’ risk assessment should also be managed as a controlled document update. When the assessment is amended, the organisation should identify the current version, withdraw superseded copies and ensure that relevant personnel are working from the revised information.
Document control is particularly important where changes affect operating instructions. Updated schematics, written procedures, inspection schedules and records should correspond with the revised assessment. Any unresolved actions should remain visible rather than being lost when an older document is replaced.
The review record should be retained with the assessment and supporting evidence, such as change-control documentation, meeting notes or updated system information. This creates a clear audit trail showing what was reviewed, why the conclusions were changed or confirmed, and which instructions apply to the water system at that point in time.
Discuss your Legionnaires’ risk assessment review
Discuss your Legionnaires’ risk assessment review with Blue Fish Water Management Ltd to identify the evidence, changes and responsibilities that should be considered.