Who needs a Legionnaires’ disease risk assessment?

The duty to assess Legionnaires’ disease risk generally falls on the person or organisation with control of premises, facilities or water systems, or responsibility for the health and safety of others who may be exposed. This includes employers, landlords, building owners, managing agents, facilities managers and organisations operating shared or complex water systems.

A formal assessment is particularly relevant where a building has hot and cold water systems, showers, cooling equipment, spa pools, whirlpool baths, humidifiers or other installations that could produce contaminated aerosols. The likelihood of harm depends on the design and condition of the system, how it is used, the temperature and condition of the water, and the vulnerability of the people exposed.

Employers and businesses

Employers must consider Legionella as part of their wider health and safety responsibilities where employees, contractors, visitors or members of the public could be exposed through work-related premises or equipment. This applies across offices, factories, warehouses, retail premises, hospitality venues, leisure facilities and other commercial sites. A business does not need to operate a cooling tower or an unusually large installation for a risk assessment to be relevant; ordinary showers, stored hot water and infrequently used outlets may also require consideration.

Landlords and property managers

Landlords, housing providers and managing agents should assess the risks created by water systems under their control, particularly in blocks of flats, sheltered housing, houses in multiple occupation, student accommodation and other properties with shared or communal services. Responsibility should be clearly allocated where a managing agent, maintenance contractor or facilities provider operates the system on the owner’s behalf. Contracting out maintenance does not automatically remove the duty to understand and manage the risk.

For a simple private dwelling with a straightforward domestic water system, a formal assessment may not be proportionate in the same way as it is for a complex, shared or commercial system. However, landlords still need to consider foreseeable risks, maintain relevant installations and take account of the age, condition and use of the property. The position can become more significant where tenants are vulnerable, water systems are shared, outlets are rarely used or residents may have limited control over temperature and maintenance.

Organisations caring for vulnerable people

Care homes, hospitals, supported-living settings and other health or social care premises require particularly careful assessment. Older people, smokers and people with impaired immunity or certain underlying health conditions are more likely to suffer serious illness if exposed. The assessment should therefore consider both the water system and the characteristics of its users, including rooms or facilities occupied by people who may be unable to report faults or avoid unsafe outlets.

Schools, colleges and public buildings

Educational establishments, local authority buildings, libraries, community facilities and other public premises may need an assessment where staff, pupils, visitors or contractors could encounter aerosol-generating water outlets. Periods of closure, low occupancy, building extensions and changes in use can create additional stagnation or alter the way the system needs to be controlled.

Industrial and specialist premises

Industrial sites may have additional sources of exposure, including evaporative cooling systems, process water, vehicle wash systems, emergency showers and equipment that generates fine droplets. The organisation responsible for the site should identify each relevant system rather than limiting the assessment to domestic hot and cold water. Where several businesses occupy one site, the duties of the landlord, principal employer, tenants and contractors should be documented and coordinated.

Who is legally responsible?

The responsible person is usually the employer, owner, landlord or person who has control of the premises or system. In some organisations, this function is delegated to a facilities or estates manager. There may be more than one responsible person, especially in a multi-occupied building, and each party must understand its own area of control. Their responsibilities commonly include:

• appointing someone competent to complete or oversee the assessment;
• identifying water systems, sources of exposure and people who may be affected;
• putting suitable control measures in place;
• keeping relevant records and maintenance information; and
• reviewing arrangements when the system, building use or occupants change.

The assessment should be suitable for the premises rather than treated as a generic document. A competent assessor will normally need information about system design, storage and distribution, outlet use, temperatures, maintenance history, occupancy and existing control measures. The resulting report should identify practical actions and clarify who is responsible for completing them.

An assessment is also appropriate when a building changes hands, a water system is altered, a new outlet or plant is installed, occupancy changes, an outbreak or suspected case is reported, or monitoring shows that existing controls may not be effective. It should not be regarded as a one-off certificate that removes the need for ongoing management.

Blue Fish Water Management can advise organisations on the scope of a Legionnaires’ disease risk assessment and the controls needed for their premises. Its wider water hygiene services include risk assessments, water testing, compliance audits, system monitoring, training and remedial works, allowing identified risks to be considered alongside the operation and condition of the water system.