Does L8 compliance require a written legionella control scheme?

A written legionella control scheme is the practical document that explains how the risks identified in a legionella risk assessment will be managed. It should translate the assessment into clear instructions for operating, monitoring and maintaining the water systems, so that responsible personnel know what must be done, how often it must be done and what action is required if results fall outside the specified limits.

The scheme should be proportionate to the complexity of the premises and the water systems. A simple system may require a relatively concise document, while a large or technically complex site may need separate procedures, schematics and records for different systems or areas. The document should be specific to the site rather than relying solely on generic guidance or a supplier’s standard template.

Although ACOP L8 does not prescribe one universal format, a suitable written scheme would normally describe:

• the water systems covered, including relevant storage tanks, calorifiers, hot and cold-water services, showers, cooling systems or other risk systems;
• the sources of risk identified by the assessment and the control measures selected to manage them;
• key operating parameters, such as temperature requirements, where temperature control is part of the strategy;
• monitoring, inspection, sampling, cleaning, disinfection and maintenance arrangements;
• the frequency of each task and the method to be used;
• the people or organisations responsible for carrying out, checking and authorising the work;
• the action to take when control limits are not achieved, equipment fails or abnormal conditions are found; and
• the records that must be retained to demonstrate that the scheme has been implemented.

It is important to distinguish the written scheme from the legionella risk assessment. The assessment identifies hazards, evaluates the level of risk and determines what controls are needed. The written scheme sets out how those controls will operate in practice. A risk assessment that identifies a risk but is not supported by workable procedures, assigned responsibilities and suitable records will not, on its own, demonstrate effective control.

The scheme should also reflect the actual way the premises are managed. It should identify the person with overall responsibility for legionella control and make clear how tasks are delegated to employees, facilities teams, contractors or specialist consultants. Delegating a task does not remove the dutyholder’s need to ensure that the work is properly specified, completed and reviewed. Contractors should receive relevant system information and their findings should be incorporated into the site’s control records.

Records are a key part of the scheme because they provide evidence that the stated arrangements have been followed. Depending on the system and risk assessment, records may include temperature checks, inspection results, monitoring data, sampling reports, cleaning and disinfection certificates, remedial actions, incidents, training records and communications with contractors. Records should be sufficiently clear to show the date, location, result, person undertaking the task and any follow-up action.

A written scheme is not a document that can be left unchanged indefinitely. It should be reviewed when there is a significant change to the water system, its use, occupancy, responsible personnel or control arrangements. It should also be reconsidered when monitoring identifies recurring failures, when remedial work alters the system, following an incident involving possible exposure, or when new information changes the understanding of the risk. The risk assessment and written scheme should remain consistent with one another.

Where a site has several buildings, systems or responsible teams, the scheme may need clear site plans, asset registers, system schematics and cross-references to task-specific procedures. These details help prevent important assets or low-use outlets from being missed and allow monitoring to be checked against the system’s design and operation.

Blue Fish Water Management Ltd can support organisations with legionella risk assessments, water testing, compliance audits, system monitoring, training and remedial works. These services can help establish whether the written scheme reflects the site’s current risks and whether the documented controls are being implemented as intended.