Please Note: This Article is 6 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 This increases the likelihood that some or all of it's content is now outdated.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.

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 6 years old. This increases the likelihood that some or all of it's content is now outdated.


    • I have looked at the form and it isn’t right. First of all when inspecting a cold water storage tank you should also check the stored water is below 20c, this is a requirement of the ACOP L8 and the Water Supply (Water Fittings) Regulations 1999.

      Just marking down you have high risk systems is not enough for a risk assessment, the systems need to be inspected as a part of the risk assessment. It just doesn’t go far enough.

      Shower heads do not need to be “run off” at 60c or above. The requirement is 50c at the outlet of inlet to a TMV valve within 1 minute. 60c presents an increased scalding risk. What about other outlets and cold water temperatures? Again this just doesn’t go far enough.

      Water heaters do not need to be “run off” at 60c. Hot water needs to be stored at temperature in excess of 60c. Not all water heaters can do 60c such as a combi boiler.

      Running off water after a void period doesn’t mean anything. Thankfully I checked with the HSE and outlets need to be flushed if infrequently used which means a week.

      I am so glad I haven’t had to pay to download your form.

  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.

  3. I often find peoples interpretations of the ACOP L8 4th Edition interesting and how they put the information across in sentences like “Landlords are only required to look out for small legionella risks and keep a record of their findings”, I think what is meant here is the risk in a domestic rented property is normally low, but what is not put across is, it doesn’t matter if the property is a house or a factory the requirements are the same, but in a home (with a smaller system) you would not expect to find higher risk systems or environments.

    I have seen landlords fearful to carry out their own risk assessments as they do not understand the ACOP L8 because they are not given the correct information. It reminds of when letting agents were writing to landlords telling them they had a legal obligation to “test” for Legionella every year and landlord groups told landlords they didn’t have to do anything at all and that nothing had changed, every one got confused and no one then carried out risk assessments. As a result the HSE had to issue specific guidance for providers of residential accomodation.

    The HSE DO NOT require regular control and prevention measures for domestic rented properties and if you do need to take action such as “Flushing out water systems prior to letting a property to remove stagnant water” they need to be effective and flushing an outlet after water is stagnant is not effective, you flush to prevent stagnant water. Stagnant water increases the risk of bacterial growth and if there is increased levels of bacteria present then just running tap is not going to get rid of it. As stagnant water increases the risk there then could be a requirement to test the water. Landlords DO NOT need to be supervised to test water, the only requirement of the ACOP L8 is that the test be done competently and samples are tested by a UKAS accredited testing service.

    A landlord may not actually need a written risk assessment but if something goes wrong a written risk assessment (dated etc) is the only real way to show that the risk of Legionella has been considered. Risk assessments DO NOT need to be reviewed annually, don’t know where that came from! The ACOP L8 require a review at least once every 2 years or if there is reason to believe the assessment is no longer valid and that the risk assessment be referred to whenever any Legionella related work is carried out. The record keeping requirement is also wrong in this article where it states “These records should be retained at least two years.” Risk assessments need to be kept longer than this, they need to be kept for the period they cover (i.e. up to 2 years) and then retained for a further 2 years so effectively they need to be kept for at least 4 years from the date they were carried out.

    I carry out Legionella work and I am one of only four businesses in the UK who carry the government endorsed Trust Mark for my Legionella Risk Assessments, I am also a highly qualified plumber. It annoys me when information is not given or explained correctly as it makes the industry look incompetent.

  4. Hi Adam, very help full article. I have a combi boiler fitted in in my 3 bedroom property. I carried out a risk assessment for the first time myself. The mixer in my kitchen had a reading of 49.2c hot water and the shower had a reading of 48.8c. All the other taps had a reading of over 50c. The cold water reading was 10.4 on all taps. I used a digital thermostat for the test. The property has been empty for six months while being renovated. Could you tell me if the reading are correct for a combi boiler. Thanks Dipak.

  5. My last Legionella risk assessment was done by a company called Safety Desk Consulting Ltd. Search for them online, as their fees are very affordable and they have a nationwide spread.

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