Please Note: This Article is 2 years old. This increases the likelihood that some or all of it's content is now outdated.

Legionella is a type of pathogenic bacteria associated with water systems, including the water tanks, pipework, showerheads and whirlpool baths often found in domestic properties. If the bacteria become airborne (in water spray, mist or vapour) then they can be inhaled by residents and have the potential to cause a range of pneumonia-like illnesses.

In 2014, 342 people were reported to be affected by legionella bacteria, which is a relatively small number, but the health effects can be serious which is why it’s essential that landlords do everything that they can to control the risks.

Guidance provided by the Health and Safety Executive – Legionnaires’ disease; the control of legionella bacteria in water systems; Approved Code of Practice L8 – sets out the guidelines and legal requirements for dutyholders in regards to managing and minimising the hazards created by legionella bacteria. As a landlord you are a dutyholder and must assess the risks in your properties.

Because domestic properties are seen as ‘low risk’ in terms of legionella, it is not necessary for a risk assessment to be carried out by a specialist unless the landlord does not feel confident to perform the assessment themselves. Landlords are only required to look out for small legionella risks and keep a record of their findings.

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The Legionella Risk Assessment Process

To carry out a legionella risk assessment landlords must have the knowledge, understanding and competency required. Landlords need to have an awareness of what legionella is, how it can affect people and how to carry out a risk assessment so that suitable control measures can be implemented. If an outbreak of legionella does occur within one of your properties then you be held responsible if your risk assessment is not sufficient. Legionella awareness training is a good starting point for all landlords.

To help with your responsibilities, download this exclusive legionella risk assessment template to use in your own properties. Use one template per property and ensure each section is complete in full.

Step 1: Identify the Hazards

The first step of a legionella risk assessment is to identify any potential sources of risk within the property. Create a list of the water systems in the property and make a note of how each of them could be a legionella hazard. The HSE states that legionella risk assessment needs to identify whether:

  • Water is stored or re-circulated as part of your system.
  • The water temperature in some or all parts of the system is between 20–45 °C.
  • There are sources of nutrients such as rust, sludge, scale and organic matters.
  • Conditions are present to encourage bacteria to multiply.
  • It is possible for water droplets to be produced and, if so, whether they could be dispersed over a wide area.

Sources of risk can be identified by sight or by consulting the property’s schematic diagram, which shows the layout of all water systems within the property.

This downloadable legionella checklist for landlords can contribute towards this step of the risk assessment process.

Step 2: Consider Who May be At Risk

This step involves making a record of who is most likely to be affected by any potential legionella bacteria in the property. This stage is essential to prove that landlords have considered who may be at risk.

Make a note of everyone who may be present in the property, including employees, contractors, residents and visitors, and then consider whether anyone may be more at risk than others, such as people in later life, children, those who smoke, those with existing illnesses or those with weak immune systems.

Step 3: Implement Control Measures

Before implementing new legionella controls take a look at any controls that are already in place in the property and consider whether these are sufficient or need updating. Suitable control measures include:

  • Implementing regular inspection and maintenance procedures.
  • Monitoring water temperatures.
  • Regularly cleaning parts of the water system, such as showerheads and baths.
  • Preventing access to water tanks and pipework by unauthorised people.
  • Flushing out water systems prior to letting a property to remove stagnant water.
  • Removing any redundant pipework.
  • Setting control parameters, such as ensuring hot water is stored above 60°C.

Monitoring bacteria levels and water testing should only be carried out by a specialist service, such as a water treatment company or consultant, and are generally not required by domestic properties due to their low level of risk. Landlords should not try to test the water or monitor bacteria levels unless they are properly supervised.

Once controls are implemented, remember to advise tenants of anything that they need to maintain. For example, regularly cleaning showerheads, not adjusting the temperature of the hot water heater and informing the landlord of any problems that they discover.

Step 4: Keep Records

The findings of the risk assessment should be written down or typed up into a document to act as proof that landlords are complying with their responsibilities. You can use this downloadable legionella risk assessment template as a guide.

A record should be kept of all identified hazards and their control measures, plus details of who the dutyholder is and a description of the water system present. These records should be retained at least two years. Landlords should also retain records of any monitoring, inspections, tests or checks carried out, and their dates, for at least five years.

Step 5: Review the Risk Assessment

Landlords should check on a regular basis to see whether there have been any changes in the property that may affect the risk assessment. It’s recommended that risk assessments are reviewed annually, plus each time changes are made or new information comes to light. For example when:

  • There are changes to the water system or its use.
  • There are changes to the use of the building in which the water system is installed.
  • New information about risks or control measures becomes available.
  • The results of checks indicate that control measures are no longer effective.
  • A case of legionellosis associated with the system has been diagnosed.

Article Courtesy of: Louise Petty, training course author for High Speed Training and a health and safety specialist.

Please Note: This Article is 2 years old. This increases the likelihood that some or all of it's content is now outdated.
©LandlordZONE® – legal content applies primarily to England and is not a definitive statement of the law, always seek professional advice.


  1. Can I ask whether this applies to external water sources such as garden ponds and water butts? An agent recently raised these as a major concern but I cannot find anything referring to external water siurces.

  2. In the UK every business or place of work must be risk-assessed for legionella bacteria and the risks posed by them. Water tanks, water heaters, hot and cold water taps, pipework, showers, cooling towers, hot tubs, water features etc. – all these elements must be checked and risk-assessed to determine how big a risk they may pose in relation to contamination by the bacteria and Legionnaires’ disease.


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