Legionella Risk Assessment Templates

Easily identify and control risk factors and keep your facility safe and disease-free

landlord doing legionella risk assessment in building

Published 2 Aug 2022

What is a Legionella Risk Assessment?

A Legionella risk assessment is a tool used by landlords, employers, and property managers to identify Legionella-related risk factors in a property, workplace, or facility and to control the risks of Legionnaires’ disease, a pneumonia-like illness caused by Legionella. Legionella risk assessment is a legal requirement for landlords and employers.

This article features the following:

Where is a Legionella Risk Assessment Mandatory?

Not all countries require Legionella risk assessment forms or testing. However, it is strongly encouraged by health professionals from different countries, as it can help stop the spread of Legionnaires’ disease. In the US, although there is no federal law requiring property managers and landlords to conduct risk assessments or testing of any sort for Legionella, many authorities have argued that it should be to help promote safer drinking water and protect public health. Officials in some states have taken to conducting their own efforts to help manage Legionella through state-specific laws, particularly for cooling towers, water systems, healthcare facilities, and other related buildings.

However, there are some countries that require legionella testing and risk assessments. These include the following:

  • The Netherlands;
  • Germany, but only for large facilities that regularly heat drinking water, have an internal water storage capacity of more than 400 liters, and have a pipeline volume of at least three liters; 
  • UK;
  • France;
  • Australia; and
  • Canada. 

Why use Legionella Risk Assessment Templates?

To help save time, others opt to use templates instead for their Legionella risk assessments. Property managers or competent individuals responsible for the control of Legionella bacteria should ensure a safe and disease-free workplace or residential accommodation for occupants. Legionella risk assessment templates aim to guide assessors to perform thorough inspections of water systems and prevent the growth of Legionella bacteria which can cause serious harm or fatality from Legionnaires’ disease.

What Should a Legionella Risk Assessment Checklist Contain?

There are many ways to create a Do-It-Yourself (DIY) legionella risk assessment form, though most forms have the following common items:

  • List of water-related hardware installed such as showers, sink faucets, and the like
  • Data on water temperature and water cooling and heating systems 
  • Disinfection steps 
  • Description of the pipework in place
  • People most at risk for contracting Legionnaires

How Do I Do a Legionella Risk Assessment?

Landlords, employers, and property managers can use the following steps as a guide in performing a Legionella risk assessment and in managing Legionella risks:

Step 1: Determine Overall Risk

The first step in carrying out a Legionella risk assessment is to determine if there is risk. Check if any of the top 3 Legionella-related risk factors are present. Also check for other Legionella-related risk factors such as:

  • Water is being stored or re-circulated as part of the water system
  • Sources of nutrients for Legionella, such as rust, sludge, scale, organic matter, and biofilms, are present
  • Water droplets are being produced or can be produced
  • Water droplets can be dispersed over a wide area (e.g., showers and aerosols from cooling towers)
  • Any employee, resident, or visitor is more susceptible to Legionella infection due to age or illness, such as a weakened immune system
  • If the person who is more susceptible to Legionella infection could be exposed to any contaminated water droplets

If there is currently no risk, determine if there is a possibility that a risk will occur. If there is no reasonably foreseeable risk, according to the HSE, the Legionella risk assessment is complete. 

If there is risk, determine the risk level. If the risk level is low and risk is being properly managed to comply with the law, according to the HSE, the Legionella risk assessment is complete. Indications that the Legionella risk level is low (based on examples given by the HSE):

  • Use of hot and cold water systems 
  • Use of small, domestic-type systems
  • Regular water usage and turnover
  • No stored water tanks

Step 2: Test for Legionella if Needed

To test for Legionella, the HSE recommends doing the following:

  • Use the BS 7592 standard for water sampling
  • Neutralize biocide if used and where possible
  • Submit water sample to a UKAS-accredited laboratory that takes part in a water microbiology proficiency testing scheme
  • Ensure that the UKAS-accredited laboratory applies the minimum theoretical mathematical detection limit of <= 100 legionella bacteria per liter of sample for culture-based methods

Aside from cases where control measures do not seem to be effective, Legionella testing is typically only carried out for cooling tower systems, though it is also recommended for other open systems such as evaporative condensers and spa pools. Although in recent years, it has also been encouraged for establishments in which water is constantly heated and cooled repeatedly, and then distributed for human use or consumption. Additionally, the HSE states that these systems should be tested for Legionella at least quarterly. However, take note that UK law does not require a Legionella test certificate, nor does the HSE recognize it

Step 3: Fulfill Other Duties

Under the UK Notification of Cooling Towers and Evaporative Condensers Regulations 1992 (NCTEC), the local authority must be notified in writing if there is a cooling tower or evaporative condenser on site and details about where it is located should be included. The local authority must also be notified when such devices are no longer in use. 

Under the UK Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR), cases of Legionellosis (Legionnaires’ disease) in employees who have worked on cooling towers or on hot and cold water systems that are likely to be contaminated with Legionella must be reported. 

For properties that are left vacant, water should not be allowed to stagnate within the water system and outlets on hot and cold water systems should be used at least once a week.

In Michigan, Flint’s water crisis spawned one of the largest outbreaks of Legionnaires’ disease in U.S. history. Here are the most common factors that make a facility more susceptible to Legionella bacteria and how landlords, employers, and property managers can effectively control them:

  1. Redundant Piping or Dead Legs

    Dead legs are improperly removed or rarely used outlet pipes without regular water flow, and such redundancy in pipeline systems lead to stagnant water, a primary breeding ground for Legionella. For example, if a sink has been removed and the piping that once led to it has been capped off, this creates an area for water to stagnate. Easily manage redundant pipework by surveying the hot and cold water system and updating its full schematic diagram, including the water flow, water treatment program, and a written scheme for controlling Legionella.

  2. Infected Cold Water Storage Tanks

    Another condition for legionella to rapidly multiply is the lack of residual disinfectants like chlorine in cold water storage tanks. Routine cleaning and disinfection of cooling towers and the hot and cold water system should take place at least once in every six months. The procedure should cover the initial concentration of oxidizing biocide in use for the pre- and post-cleaning disinfection stages, contact time for each stage, and methods for carrying out the cleaning, including the removal of packing.

  3. Lukewarm Water Temperature

    The temperature of hot and cold tap water should remain 50 degrees Celsius (122°F) or above and 20 degrees Celsius (68°F) or below, respectively, while the water temperature inside the boiler should be kept at or above 60 degrees Celsius (140°F). Legionella exponentially grows in warm water temperatures, ranging from 25-42 degrees Celsius (77°-108°F). Proactively guard the premises against Legionnaires’ disease by installing temperature sensors.

Automate Temperature Readings and Gain Real-time Alerts

Property managers can effectively prevent Legionellosis in their premises by regularly maintaining the condition, cleanliness, and correct temperature of hot and cold water systems. Turn your paper Legionella risk assessment forms into digital templates and record your significant findings with the convenience of using iAuditor, the world’s most powerful mobile risk assessment app.

FAQs about Legionella Risk Assessments

According to the Health and Safety Executive (HSE), anyone with the necessary skills, knowledge, and experience to manage health and safety can do a Legionella risk assessment.

Most landlords, employers, and property managers can do a Legionella risk assessment on their own. But if they are not comfortable with doing it on their own or if they are unable to do the Legionella risk assessment, they can appoint someone else to do it on their behalf.

Though the HSE has not given a specific timeframe for how often Legionella risk assessments need to be done, based on the Approved Code of Practice for Legionnaires’ disease (ACOP L8), records of significant findings must be kept for the period that they are current and at least 2 years after the Legionella risk assessment. Therefore, it is recommended that Legionella risk assessments are reviewed and, should there be changes that could affect the risk, be done at least every 2 years.


According to ACOP L8, a Legionella risk assessment should be reviewed when there is reason to believe that it is no longer valid. Examples of when a Legionella risk assessment should be reviewed (taken from HSE guidance for ACOP L8): 

  • 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 has become available
  • Checks have indicated that control measures are no longer effective
  • There are changes to key personnel
  • A case of Legionnaires’ disease has been associated with the water system

Yes, Legionella can be found in houses or residential buildings. Although most laws on Legionella are focused on businesses, Legionella can be found in any establishment that has natural water and/or hot and cold water systems. This includes private homes. However, private homes are considered to be at low risk of Legionella, as their water systems are often less complex than businesses’. The water systems of private houses are also used more frequently, allowing for water to continuously flow and not be stagnant. 

Legionella testing and Legionella risk assessments are not required for households. However, If a homeowner wants, they can still have their houses examined for the bacteria similar to how businesses do so. Alternatively, homeowners can also DIY their own legionella risk assessments, but would still have to consult a professional for further assistance.

safetyculture content specialist shine colcol

SafetyCulture Content Specialist

Shine Colcol

Shine Colcol is a content writer and researcher for SafetyCulture since 2019, mostly covering topics about health and safety, environmental, and operations management. She is passionate in empowering teams to build a culture of continuous improvement through well-researched and engaging content. Her experience in cross-industry digital publishing helps enrich the quality of information in her articles.

Shine Colcol is a content writer and researcher for SafetyCulture since 2019, mostly covering topics about health and safety, environmental, and operations management. She is passionate in empowering teams to build a culture of continuous improvement through well-researched and engaging content. Her experience in cross-industry digital publishing helps enrich the quality of information in her articles.