Who is responsible for arranging legionella testing?

Responsibility for arranging legionella testing rests with the dutyholder who controls the premises, water system or relevant work activity. This may be an employer, landlord, managing agent, facilities manager, housing provider or another appointed person. The dutyholder must use the findings of the legionella risk assessment to decide whether sampling is needed, select a suitably competent provider and ensure that the results lead to appropriate action.

Under the Health and Safety at Work etc. Act and the Management of Health and Safety at Work Regulations, organisations must assess and control risks to people affected by their activities. The Health and Safety Executive’s Approved Code of Practice L8 and HSG274 provide the principal guidance for controlling legionella in workplaces and other relevant premises. These duties cannot be transferred simply by appointing a contractor: a specialist can carry out the technical work, but the organisation in control remains responsible for managing the risk.

Who normally arranges the testing?

• Employers: The employer is usually responsible for systems serving its workplace, unless control has been formally assigned to another organisation.
• Landlords and property owners: They are generally responsible for assessing and managing risks from water systems under their control. The exact division of duties may depend on the lease, tenancy agreement and the type of property.
• Managing agents and facilities managers: These parties may arrange assessments, sampling and remedial work on behalf of the owner or occupier. Their authority and responsibilities should be set out clearly in the management agreement.
• Building occupiers: A tenant or operating business may be responsible for water systems it controls, even where the building itself is owned by another party.
• Principal contractors and other dutyholders: Where several organisations share a building or project, each must manage the part of the risk it controls and cooperate with the others.

A business should nominate a named responsible person rather than treating legionella control as an undefined organisational task. That person does not necessarily need to perform sampling personally. They do need sufficient authority, knowledge and resources to arrange competent work, review findings, maintain records and escalate unresolved risks.

Does the dutyholder always have to arrange testing?

No. Legionella testing is not automatically required for every building or water system. The risk assessment should consider factors such as water temperature, storage and distribution arrangements, stagnation, infrequently used outlets, system complexity, vulnerable occupants and the potential for exposure to water aerosols. It should also consider previous results, control failures, changes to the system and any remedial work.

Where the assessment concludes that routine or investigative sampling is appropriate, the dutyholder should ensure that the frequency and locations are justified by the risk. Testing may be particularly relevant where temperature control is difficult, the system is extensive or complex, there is a history of positive results, or people who may be more susceptible to serious illness could be exposed. Conversely, arranging samples without understanding the system can produce results that are difficult to interpret and may fail to address the underlying control problem.

What remains the dutyholder’s responsibility when a contractor is used?

1. Provide the contractor with accurate information about the premises, water systems, access restrictions and known hazards.
2. Check that the organisation and individuals carrying out the work are competent for the required sampling, interpretation and reporting tasks.
3. Agree the sampling plan, including the outlets or points to be sampled, the reason for sampling and the action to be taken if results are unsatisfactory.
4. Ensure samples are collected, transported and analysed using appropriate procedures.
5. Review the report rather than filing it without action. Results must be considered alongside temperatures, maintenance records, system changes and the current risk assessment.
6. Arrange investigation and remedial work where results, observations or trends indicate a loss of control.
7. Keep suitable records, including the assessment, sampling plan, laboratory reports, decisions, corrective actions and evidence that actions were completed.

Where a positive result is reported, the laboratory result alone does not determine the response. The dutyholder should consider the result in context, check whether control measures are operating as intended and obtain competent advice on any necessary investigation, disinfection or system changes. Urgent escalation may be appropriate where there is significant exposure potential or a vulnerable population.

Responsibility can be shared contractually, but it should never be ambiguous. Contracts should state who maintains the asset, who monitors temperatures, who arranges sampling, who receives reports, who authorises remedial work and who communicates significant findings. A clear allocation prevents missed samples and delays when a result requires action.

Blue Fish Water Management Ltd can support dutyholders with risk-led legionella sampling, water testing, compliance reviews, monitoring and remedial advice. The client remains responsible for retaining control of its legal duties, while the appointed specialist provides the technical work and information needed to support informed water safety decisions.