Control of Legionella in hot and cold water systems in care services / settings using temperature

SIM 07/2012/07


1 This SIM gives guidance to Inspectors on managing the risks from Legionella in hot and cold water systems. It is relevant to all care services / settings where there are people at higher risk of contracting Legionnaires disease. It summarises key controls, directs Inspectors to further guidance and outlines enforcement expectations.


2 This SIM sets out the key requirements for managing the risk from the potential growth and proliferation of Legionella bacteria in different hot and cold water systems commonly found in care settings.

3 It will assist Inspectors in deciding whether adequate arrangements are in place to control the risk from Legionella and the enforcement action required.

4 It applies to premises where temperature is used to control risk. Some premises use additional or alternative risk controls. These include:

  • copper and silver ionisation,
  • UV radiation,
  • chlorine dioxide,
  • ozone.

5 Where such control methods are used, particularly as an alternative to temperature control, inspectors should be satisfied that they are being maintained and monitored to ensure their effectiveness.


6 Inspectors should use this SIM as a guide when carrying out proactive or reactive interventions.


7 Those at high risk from contracting Legionnaires' disease include older people, those with respiratory disorders and the immuno-compromised. As well as care homes, people at particular risk may be present at hostels, staffed and sheltered housing for older people, day care services or other similar settings. Experience shows that many care providers are not adequately managing the risks from Legionella.

8 The Health Protection Agency (HPA) has identified that a high percentage of people in the UK contract Legionellosis in the 'community'. The source is often not identified. However, people who use care services are at increased risk and it is important that assessment and simple effective controls are in place at such settings to reduce the risk, so far as is reasonably practicable.

9 The types and sizes of hot and cold water systems range from instantaneous heating of water with no storage through to numerous hot water storage cylinders (calorifiers) and cold water tanks. Distribution systems vary in complexity, from simple direct water distribution to circulating hot water loops on different levels with a mixture of cold storage tanks and direct mains fed outlets. Each will have a different level of risk depending on complexity, materials used and population present. Information on different types of hot and cold water systems can be found in Appendix 2.

Risk management

10 Guidance on risk assessment and control measures can be found in Appendix 1.



11 Inspectors should be aware of FOD training in controlling the risks from Legionella (http://intranet/learning/fod/courses/control-of-legionella.htm). To assess controls they will need access to an immersion / surface temperature probe.


12 The Health and Social Care Services Unit would welcome information about any incidents, enforcement action or initiatives on this issue. Contact via: [email protected].

Role of other regulators

13 Health and social care is also regulated by others in England, Scotland and Wales, and Inspectors should be aware of the relevant agreements / high level statements. Further information can be found on the 'who regulates health and social care' webpage.

14 The Health Protection Agency (HPA) lead on public health issues in England and Wales. Legionella is a notifiable disease to HPA via Local Authority Proper Officers under the Health Protection (Notification) Regulations 2010. In Scotland Registered Medical Practitioners should notify Health Protection Scotland (HPS) under Part 2 (Notifiable Diseases, Organisms and Health Risk States) of the Public Health etc. (Scotland) Act 2010 via Health Boards.

15 Health and Safety at Work Etc Act 1974, (HSWA Ss 2 and 3), Management of Health and Safety at Work Regulations 1999 (MHSWR Reg.3) and Control of Substances Hazardous to Health Regulations 2002 (COSHH) apply.

16 Certain cases of Legionellosis to employees are reportable under RIDDOR if a doctor notifies the employer. Further guidance on RIDDOR is available.

Risk of ill-health / serious injury

17 In determining the risk of ill-health, Inspectors need to consider:

  • the vulnerability / susceptibility and likelihood of employees or non-employees contracting the disease if they were to be exposed to harmful levels of Legionella bacteria;
  • the risk posed by the water system; and,
  • the adequacy of the control measures.


18 The potential risks presented by Legionella bacteria are well known and publicised. The Health and Social Care Services Unit supports enforcement action where failings in risk management systems give rise to significant risk to vulnerable people.

19 Where the susceptibility to contracting the disease and risk is immediate, a prohibition notice (PN) may need to be considered. For example, where water sampling reveals potentially harmful levels of Legionella bacteria (See Legionnaires' Disease: The control of legionella bacteria in water systems (L8)) and susceptible individuals are likely to be showered / bathed before adequate action or controls are put in place to reduce the risk.

20 Enforcement action should also be considered where people are vulnerable / susceptible to contracting the disease and there is an inadequate risk assessment, where the hot and cold water system has the potential to allow Legionella bacteria to proliferate, or there are inadequate controls in place.

21 Determining appropriate enforcement action requires HSE inspectors to refer to Enforcement Management Model (EMM). OC 130/5 provides guidance on the use of EMM in relation to health risks.

Compliance standards

Defined standards

22 The ACOP L8 provides a basic framework for controlling exposure to the organism; provides advice on HSWA and COSHH; and on the management, selection, training and competence of personnel. It also sets out the responsibilities of manufacturers, importers, suppliers and installers of products and services.

Established standards

23 HSG220 Health and safety in care homes - issued 12/01 (being revised) sets out the standards necessary when using temperature as the primary control to manage risks. It also refers to other control methods (eg copper and silver ionisation) and the need for maintenance.

24 Department of Health, Technical Memorandum (HTM) 04-01 (available electronically from the NHS 'Space for Health' information portal): 'The control of Legionella, hygiene, "safe" hot water, cold water and drinking water systems Part A: Design, Installation and testing' applies to both old and new healthcare sites. Scottish equivalent is SHTM 2040 'Control of Legionella in Health Care Premises – a Code of Practice' and SHTM 2027 'Hot and Cold Water Supply, Storage and Mains Services'.

Administrative arrangements

25 There may be circumstances where administrative arrangements, such as the keeping of records, are not complied with. If the issue / activity does not have a direct impact on risk, or the effect of non-compliance is not immediate, it should be dealt with via the EMM compliance / administrative arrangements route.

26 In such cases the initial enforcement expectation should be determined by use of Table 5.2 'Compliance and administrative arrangements: Initial enforcement expectation'. Further information can be found at: http://intranet/strategy/cost-recovery/inspector-support/emm-question-and-answer.htm

Further information


Is this page useful?