Who is required to have a legionella risk assessment?If you are an employer, or someone in control of premises, including landlords, you must understand the health risks associated with legionella.As an employer, or a person in control of the premises, you are responsible for health and safety and need to take the right precautions to reduce the risks of exposure to legionella.The key element from the ACOP is for a Risk Assessment to be carried out on water services liable to give conditions, which may promote the growth of Legionella bacteria and dissemination to atmosphere. Where the assessment demonstrates that there is no reasonably foreseeable risk, or that the risks are insignificant and unlikely to increase, no further assessment or measures are necessary. Where the assessment shows that there is a reasonably foreseeable risk; the use of water systems should be controlled or prevented so far as reasonably practicable from that risk. The scheme of control is created to minimise the risk should contain such information about the system as is necessary to control or prevent the risk of exposure to Legionella bacteria, including: -a) An up-to-date plan showing the basic layout of the system, including parts which are temporarily out of use.b) Identification of the system structure.c) A description of the correct and safe operation.d) The precautions to be taken.