Who decides how often a legionella risk assessment is reviewed?

The dutyholder retains ultimate responsibility for deciding how often a legionella risk assessment is reviewed. This responsibility may be delegated operationally to an appointed responsible person, but appointing someone else does not remove the dutyholder’s legal responsibility to ensure that the assessment remains suitable, sufficient and up to date.

In practice, the decision is usually made through a combination of management oversight and competent technical advice:

• The dutyholder has control of the premises, water systems or business activities and is accountable for making sure legionella risks are properly managed.
• The responsible person manages the arrangements on the dutyholder’s behalf. They may set the review programme, arrange assessments, monitor actions and escalate changes in risk.
• The competent risk assessor examines the water systems and management controls, identifies hazards and recommends an appropriate review interval based on the findings.
• Specialist advisers or water hygiene professionals may provide supporting information, testing or technical recommendations where the system is complex or the risk profile changes.

The assessor does not normally take over the dutyholder’s legal obligations. Their role is to provide competent, evidence-based advice. The dutyholder or responsible person must then consider that advice, approve suitable arrangements and ensure that recommended actions are completed.

A review interval should be recorded in the organisation’s written water safety arrangements. The record should explain why that interval has been selected, who is responsible for arranging the review and what events would require an earlier assessment. This creates a clear audit trail and helps prevent the review date from being treated as an isolated administrative task.

When deciding whether the existing interval remains appropriate, the responsible person should consider the assessment’s findings and the effectiveness of the control scheme. Relevant considerations include:

• the complexity, size and condition of the water system;
• the susceptibility of people who may be exposed to contaminated aerosols;
• the reliability of temperature control, monitoring, cleaning and maintenance;
• whether control measures have been completed and remain effective;
• the competence, continuity and resources of the people managing the system; and
• any deficiencies identified through inspections, monitoring records, incidents or audits.

There is no universal review interval that is suitable for every premises. An organisation may choose to review its assessment at a planned interval as part of its management system, but a calendar date alone is not enough. The interval needs to be defensible in relation to the actual risk, and it should be reconsidered whenever the basis for the original assessment changes.

It is also important to distinguish between a formal review and routine monitoring. Regular checks of temperatures, sentinel outlets, tanks, control measures and maintenance records help identify whether the system remains under control. These checks do not replace a formal review when there has been a material change or when monitoring indicates that existing arrangements may no longer be adequate.

A review should be brought forward after events such as alterations to the water services, a change in building use or occupancy, periods of inactivity, changes to responsible personnel, changes in management arrangements, a suspected or confirmed case of legionellosis, or repeated failures in control measures. The need for an earlier review may also arise when relevant guidance changes or when an audit raises concerns about the assessment’s assumptions.

For multi-occupied buildings or properties managed under contract, responsibilities should be clearly allocated between the owner, managing agent, employer, facilities team and specialist contractors. The written arrangements should identify who has authority to commission a review, who supplies system information and who verifies that remedial actions have been addressed. Shared responsibility without clear ownership can leave important review decisions unresolved.

Blue Fish Water Management can help dutyholders and responsible persons interpret assessment findings, define a proportionate review programme and identify the evidence needed to support it. Its legionella risk assessment, water testing, compliance audit and system monitoring services support informed water safety decisions for organisations nationally.