Legionella procedure

This procedure replaces all previous corporate policies and procedures relating to Legionella.


This procedure sets out a consistent approach to managing the risks associated with legionella in Hampshire County Council (HCC) properties.  The aim is to prevent exposure to legionella in these properties and secure compliance with the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health Regulations 2002.


This procedure does not cover the natural environment, e.g. ponds, lakes, canals and rivers where legionella can also exist.

The procedure covers:

  • An overview of the arrangements
  • Risk assessment
  • Roles and responsibilities

Legionella - a type of bacteria which is common in natural water sources such as rivers and lakes.  It can contaminate and grow in man-made water systems, such as hot and cold water systems in buildings and misting/spraying systems in greenhouses.  It thrives at temperatures between 20°C and 50°C, particularly if the water system contains deposits such as sludge, scale or organic matter.  It is killed either by elevated temperatures or chemical treatment.

Legionnaires’ disease - a form of pneumonia caused by legionella bacteria.  It is normally contracted by inhaling small droplets of water (aerosols), suspended in the air, containing the bacteria.

Vulnerable groups and individuals - anyone is susceptible to infection, but those at higher risk include people aged over 45, smokers and heavy drinkers, people suffering from chronic respiratory or kidney disease, diabetes, lung and heart disease, or anyone with an impaired immune system.

Responsible Manager (RM) - the person who is the main lead for a site, for example the Head Teacher at a school, Depot Manager at a transport depot, Senior Ranger in The Countryside Service, Registered/Unit Manager.

Nominated Responsible Person (NRP) - the person to whom the site manager has delegated the local legionella monitoring responsibilities.  The NRP must be someone who is familiar with the water system, for example the site manager or caretaker.  Arrangements should be in place to cover absences of the NRP.

Overview of arrangements

On behalf of HCC, Property Services fulfils the function of competent person for legionella.  Property Services prioritise resource to minimise risks based on information collected from the field.  To do this, sites are required to provide accurate data on water temperatures and undertake local actions (such as flushing of taps) under the guidance of Property Services.  This information and instruction is provided through an online portal/system called Records for Buildings (RfB).

Further, every property for which HCC is a duty holder, will have an up-to-date technical risk assessment (survey and schematic drawing) for its water system, arranged and used by Property Services when considering appropriate actions.

To ensure that these remain up-to-date, Property Services must be informed of any locally-procured work on water systems via legionella@hants.gov.uk.

The Responsible Manager (RM) for each HCC property will appoint a Nominated Responsible Person (NRP) to carry out the local control measures and complete the monthly online monitoring form.

Further technical support is provided by Hampshire Scientific Service (HSS) as needed.

All reasonably practicable precautions will be taken to prevent exposure to legionella.

Risk Assessment

HCC is legally required to record the significant findings of its legionella risk assessment.

Given the purpose of HCC’s buildings, and the population demographic of those who use them, legionella presents a significant risk if left uncontrolled. All HCC buildings and water systems will therefore be managed in a way to control this level of risk. On this basis, there is no need for individual buildings to be risk assessed separately. However, certain sites whose users are more likely to be a high risk population are prioritised for remedial action where necessary.

This procedure documents the significant findings of The Council’s risk assessment for this risk.

Roles and reponsibilities

Property Services

Property Services will:

  • Act as the competent person for the management of legionella risks in HCC properties.
  • Arrange and provide up-to-date technical risk assessment surveys and schematic drawings for the water systems in all HCC properties.
  • Ensure that the design and construction of all water systems in HCC properties are fit for purpose and enable correct water temperatures to be maintained.
  • Ensure that term maintenance contracts are in place to maintain the water systems in all HCC buildings.
  • Ensure that all sentinel outlets are properly identified and marked up for monthly temperature monitoring purposes and where suitable provided with fixed monitoring points.
  • Provide and manage the online monthly monitoring form.
  • Take appropriate action if the monthly monitoring system identifies abnormal situations in a water system, e.g. cold water temperatures above 20oC or stored hot water temperatures below 60oC. (Appendix 1 - HBI flowchart)
  • Take appropriate action in response to any other reports of abnormal situations in a water system.
  • Ensure that any remedial work is specified and completed adequately.
  • Ensure that cold water storage tanks are inspected and cleaned at least annually.
  • Ensure that calorifiers are drained and inspected at least annually.
  • Arrange any surveys, testing or other work that may be identified as required on water systems in HCC properties.
  • Ensure that contingency plans are in place if water systems are found to have been contaminated with legionella.
  • Give reasonable consideration of the characteristics of the site and users to prioritise resource.
  • Arrange for database log on details to be sent to RM.


Responsible Manager (RM)

A responsible manager must be appointed for each site and details sent to Property Services.

The RM must:

  • Appoint a Nominated Responsible Person (NRP) to carry out water temperature monitoring, descaling, disinfecting, system flushing and complete the online monthly monitoring form.
  • Ensure the NRP has sufficient knowledge and understanding to be competent in delivering their role.
  • Ensure that the NRP is delivering the items listed above, as directed through the on line monitoring form.
  • Make arrangements to cover the NRP’s responsibilities during periods when the NRP is not present.
  • Work with Property Services to support local contingency plans if a water system is found to have been contaminated with legionella.


Nominated Responsible Person (NRP)

The NRP must:

Undertake the day to day actions for the management of the water system on site, including:

  • Carrying out monthly water temperature monitoring at sentinel outlets and a rolling sample of other outlets.
  • Carrying out quarterly descaling and disinfecting of water outlets such as showers, sprays and misters.
  • Flushing out any parts of a water system that have not been used within the previous seven days.
  • Complete the online monthly monitoring database accurately and within the required timeframe.
  • Following the guidance laid out on the RfB database specific to their buildings.


Hampshire Scientific Service (HSS)

HSS will:

  • Carry out any water testing for legionella bacteria on request.
  • Provide advice to Property Services, RMs and NRPs following any positive tests for the presence of legionella in water systems.

Training on how to undertake these tasks is contained the RfB database and can be accessed at any time by logging onto the system.



Appendix 1 - HBI flowchart

Printable version of procedure

The full procedure is available as a printable document Corporate health & safety procedure - Legionella - Issue 5 - 2018-09

Section 2 – Escalation process for Property Services Legionella & Health and safety Advisers only