How much disruption does a Legionnaires’ disease risk assessment cause?

A Legionnaires’ disease risk assessment is normally a low-disruption compliance activity, rather than a building works project. Its purpose is to understand how a water system is designed and operated, identify conditions that could allow Legionella growth or spread, and record the controls needed to manage the risk. The assessment itself should not usually interrupt normal business operations for a prolonged period. Any greater disruption generally relates to gaining safe access to particular areas, coordinating with site activities or carrying out additional investigations.

The practical impact depends on the premises and the way its water systems are used. A straightforward office with accessible plant and a simple domestic water system is likely to involve fewer operational constraints than a site with several buildings, specialist equipment, accommodation areas, vulnerable occupants or processes that cannot easily be paused. Arrangements may also need to take account of restricted rooms, controlled zones, security procedures, hygiene requirements and activities where an assessor cannot enter without an escort.

Before the assessment, the responsible person or facilities team can reduce avoidable interruption by preparing:

• existing water system schematics, asset lists and maintenance information;
• records of temperature checks, cleaning, disinfection, sampling and previous remedial work;
• details of infrequently used outlets, closed areas, changes to occupancy and known system alterations;
• site access instructions, permits, induction requirements and relevant health and safety information; and
• contact details for staff who understand the building, its water services and its day-to-day use.

Good preparation helps the assessor work methodically and reduces the need to revisit areas because information or access was unavailable. It also allows the site team to identify sensitive operations in advance. For example, an assessment may need to be coordinated around patient areas, production activities, tenant access, resident welfare or other functions where an unplanned interruption would be unacceptable.

Access to plant rooms, tanks, boilers, calorifiers, outlets and other relevant assets should be planned with the person responsible for the premises. The assessor may need to observe how outlets and equipment are used, check whether assets correspond with available records, and establish whether control measures are practical in the real operating environment. These activities can often be incorporated into normal facilities management arrangements, but they should not be treated as an entirely desk-based exercise.

It is important to distinguish the assessment from the work that may follow it. A risk assessment identifies hazards, weaknesses and recommended controls; it does not automatically mean that pipework will be replaced, tanks modified or systems disinfected during the same visit. If significant risks are identified, remedial measures may require separate planning, quotations, isolations or shutdowns. Those works can be more disruptive than the assessment itself, particularly where they affect shared services or critical water supplies. The findings should therefore explain which actions are urgent, which can be programmed, and what operational controls are needed in the meantime.

Where sampling or further technical investigation is appropriate, this should be agreed as part of the scope. Sampling may add coordination requirements because outlets or parts of the system may need to be identified accurately and made available for collection. It does not, by itself, mean that the whole water system must be taken out of service. Any proposed isolation, temperature adjustment, cleaning or disinfection should be communicated beforehand, with consideration given to affected users and alternative arrangements.

For occupied or multi-tenant premises, communication is often the main factor in preventing avoidable disruption. The responsible person should decide who will provide access, who will receive findings and how occupants, tenants or operational managers will be informed about any temporary restrictions. A written schedule and clear site contact can prevent duplicated instructions and help distinguish assessment activity from later remedial work.

Blue Fish Water Management Ltd approaches the assessment as a practical review of how the system is managed, not simply as a document exercise. Its recommendations can be aligned with the way the premises operates, while still addressing relevant water safety risks. For a business planning an assessment, the key question is not whether there will be any site activity, but how access, information and any follow-on controls can be organised so that the review is proportionate and operational impact remains controlled.