Appendix 1 - risk management system

When inspecting or investigating, Inspectors should look at the Legionella risk management system:

Risk assessment

The ACOP L8 and COSHH places responsibility on employers and others to:

  1. identify a competent person;
  2. identify and assess risks of Legionellosis; who may be harmed, what risk does the hot and cold water system pose, what controls exist to reduce the risk;
  3. avoid the use of systems that give rise to a reasonably foreseeable risk of Legionellosis or, where this is not reasonably practicable, prepare a written scheme for minimising the risk from exposure;
  4. implement and manage the scheme of precautions including the appointment of a person, or persons, to take managerial responsibility and to provide supervision; and,
  5. keep appropriate records.

The assessment should address the risks from the system and how they are controlled. It should include details of:

Records of operation, monitoring and remedial work should be kept.

If water treatment or any other task is performed by a contractor then the respective responsibilities of the occupier and the contractor must be clear.

Control measures

A summary of the main requirements for a hot and cold water system utilising temperature as the means of Legionella control can be found in Appendix 3 and below.

Cold Water Storage tank

Hot Water Storage Cylinder

Hot and Cold Water Distribution System

*Note - TMVs should ideally only be used where people are at risk of scalding


It is essential that the control measures identified are maintained long term to minimise bacterial growth. In addition:

Where failures are found, a robust system should be in place to ensure corrective action is taken.


Staff involved in maintaining hot and cold water systems must understand the risks and the precautions needed to control them. A nominated competent person should be appointed to oversee the management of Legionella risk at care settings. This person should be competent to ensure that the risk is adequately assessed and controlled so far as is reasonable practicable.

They should have sufficient authority to ensure that the controls identified through the assessment are properly implemented and maintained. Competent persons need to be aware of systems or equipment that requires specific maintenance or cleaning to ensure it remains effective.