How to Conduct a Legionella Risk Assessment

Legionella bacteria can pose a serious health risk, leading to Legionnaires’ disease, a potentially fatal form of pneumonia. Conducting a Legionella risk assessment is a crucial step in preventing outbreaks and ensuring the safety of your property and its occupants. This guide will walk you through the process, providing a step-by-step approach to conducting a thorough assessment.

What is a Legionella Risk Assessment?

A Legionella risk assessment is a systematic evaluation of your water systems to identify and assess the potential risks associated with Legionella bacteria. The goal is to determine if there are conditions present that could encourage the growth and spread of Legionella and to implement appropriate control measures.

Step-by-Step Guide to Conducting a Legionella Risk Assessment

1. Identify and Understand Your Water Systems

   • Begin by mapping out all water systems on your property, including hot and cold water systems, cooling towers, spa pools, and any other water features.
   • Understand how these systems operate, including water flow, temperature, and storage.
   • Identify any areas where water could stagnate or where temperatures could reach the ideal range for Legionella growth (20-45°C).

2. Identify Potential Sources of Risk

   • Look for areas where water could stagnate, such as dead legs in pipework or infrequently used outlets.
   • Assess the temperature of your water systems. Legionella thrives in warm water.
   • Check for the presence of deposits or biofilm, which can provide nutrients for Legionella growth.
   • Consider any areas where aerosols could be created, such as showers or cooling towers.

3. Assess the Likelihood of Exposure

   • Determine who is at risk of exposure to Legionella, including employees, residents, visitors, and the public.
   • Consider the vulnerability of individuals, such as the elderly, those with weakened immune systems, or smokers.
   • Evaluate the frequency and duration of potential exposure.

4. Evaluate the Risks

   • Based on your findings, assess the overall level of risk.
   • Consider both the likelihood of exposure and the potential severity of harm.
   • Prioritise risks based on their significance.

5. Implement Control Measures

   • Develop and implement a Legionella control scheme to minimise risks.
   • Control measures may include:
     • Maintaining hot water temperatures above 60°C and cold water temperatures below 20°C.
     • Regularly flushing infrequently used outlets.
     • Cleaning and disinfecting water systems.
     • Monitoring water temperatures and conducting regular testing.
     • Removing or modifying dead legs in pipework.
   • Document all control measures and keep records of maintenance and testing.

6. Document Your Findings

   • Record all findings from your risk assessment, including identified hazards, assessed risks, and implemented control measures.
   • Keep detailed records of all maintenance, testing, and monitoring activities.
   • Ensure that your risk assessment is easily accessible and regularly reviewed.

7. Regularly Review and Update Your Assessment

   • Legionella risk assessments should be reviewed regularly, especially if there are changes to your water systems or if new risks are identified.
   • Review your assessment at least every two years, or more frequently if required.

8. Training and Competence

   • Ensure that those conducting the risk assessment are competent and have received appropriate training.
   • Provide training to all employees on Legionella awareness and control measures.

Why Conduct a Risk Assessment?

• Legal Compliance: It’s a legal requirement for many businesses and property owners.
• Protect Public Health: Prevents outbreaks of Legionnaires’ disease.
• Reduce Liability: Demonstrates due diligence and minimises potential legal risks.
• Maintain Property Value: Shows responsible management.

Conducting a Legionella risk assessment is an essential part of maintaining a safe and healthy environment. By following these steps, you can effectively identify and control Legionella risks, protecting your property and the people within it. Find out more about protecting people from Legionnaires’ Disease, or consider attending our Legionella Awareness Course.