We have produced some practical guidance on producing your own legionella risk assessment including templates that will work on compatible mobile devices.

The Health and Safety Executive (“HSE”) has announced a revision to the Approved Code of Practice (ACOP) and guidance Legionnaires’ disease: The control of legionella bacteria in water systems and the changes affect landlords in the private rented sector.

The HSE has issued information providing essential information for providers of residential accommodation about the changes to the approved code of practice that will affect landlords or letting agents.


What is legionella and Legionnaires’ disease?

Legionella are bacteria that are common in natural (rivers and lakes etc) and artificial water systems, eg hot and cold water systems (storage tanks, pipework, taps and showers). Legionella can live in smaller water supply systems used in homes and other residential accommodation. Other potential sources of legionella include spa and whirlpool baths, humidifiers (in factories) and fire-fighting systems (sprinklers and hose reels). Legionella can survive in low temperatures, but thrive at temperatures between 20C and 45C. High temperatures of 60C and over will kill them.

Legionnaires’ disease is a potentially fatal form of pneumonia caused by the legionella bacteria. It can affect anybody, but some people are at higher risk including those over 45, smokers and heavy drinkers, those suffering from chronic respiratory or kidney disease, and people whose immune system is impaired.

What are the changes to the ACOP?

The most significant change for landlords and letting agents, is the removal of the 300 litre limit for hot and cold water services. This was an artificially chosen limit and its removal means that all premises with a water system are now within the scope of the revised ACOP. Also, recent research shows that legionella does occur in smaller domestic systems.

Practical guidance on how to comply with the new legal responsibilities regarding control of legionella is given in the ACOP. Important changes that have been made to the ACOP and guidance include:

  • keeping records for a minimum of five years;
  • water treatment companies and consultants must show their service is effective;
  • recommended guidance linked to the appropriate sections of the ACOP;
  • details on all aspects of risk assessment control;
  • inclusion of tables which detail the monitoring requirements for cooling towers, and hot and cold water systems; and;
  • a new title.

Assessing the risk

Although the generally high throughput and relatively low volume of water held in smaller water systems reduces the likelihood of the bacteria reaching dangerous concentrations, you must still carry out a risk assessment to identify and assess potential sources of exposure. You must then introduce a course of action to prevent or control any risk you have identified.

According to the guidance, it should be possible for you to assess the risk yourself, but if you do not feel you have the right skills, you can obtain help and advice from a consultant.

When you do the risk assessment, consider the following:

  • Are conditions right for the bacteria to multiply, eg is the water temperature between 20 degrees celsius and 45 degrees celsius?
  • Are there areas where stagnant water occurs (deadlegs), eg pipes to a washing machine that is no longer used?
  • Are there infrequently used outlets, eg showers, taps?
  • Is there debris in the system, such as rust, sludge or scale (often a problem in old metal cisterns), that could provide food for growing legionella?
  • Are there thermostatic mixing valves that set a favourable outlet temperature for legionella growth?
  • Are any of your employees, residents, visitors etc vulnerable to infection, eg older people, those already ill?

Answering ‘yes’ to any of these questions suggests there is an increased risk of your tenants being exposed to legionella and falling ill in which case you need to refer to the ACOP for guidance on the action you should take. Any action taken might include the following:

  • ensuring water cannot stagnate anywhere in the system, eg remove redundant pipework, tell the tenant to run taps / showers in unoccupied rooms;
  • keeping water cisterns covered, insulated, clean and free of debris;
  • insulating pipework;

The assessment should be periodically done including when there is a change of tenant and in particular if a vulnerable tenant occupies the property (for example elderly).

Housing Health and Safety Rating System

Where a local authority inspects a property under the HHSRS, Legionella is a consideration under hazard 18 – Water Supply as shown in the operating guidance.

Useful links

A useful page with various additional information and links about Legionella / Legionnaires’ Disease and risk assessment forms is available here