In the UK, there are around 200-250 cases of Legionnaires’ disease reported each year.
A Legionella risk assessment is a vital process in assessing the likelihood of the growth and spread of Legionella bacteria in a building’s water systems.
This evaluation aims to identify potential sources of contamination, determine the risk level for individuals who may come into contact with contaminated water, and establish measures to control or prevent bacterial spread.
A Legionella risk assessment should form part of your compliance schedule.
The procedure typically involves a site visit, where a Legionella risk assessor inspects the water systems and identifies potential sources of bacteria, such as water storage tanks, cooling towers, spas, plumbing, and other water systems. The assessor evaluates the risk level of each potential source, considering factors like water temperature, system age and condition, and frequency of use.
Water Sampling
Sampling and analysis may be necessary, with water samples taken from different parts of the system to test for the presence of Legionella bacteria. The findings are then documented in a report, outlining any identified sources of bacteria, the associated risk levels, and recommended measures for controlling the risk.
Control Measures
Control measures may include cleaning and disinfecting the water system, regular maintenance schedules (often referred to as PPM – Planned Preventative Maintenance), and modifying the water system design. It’s crucial to periodically review the risk assessment report and re-evaluate the water system for potential sources of Legionella bacteria, especially if there are any changes to the system or its usage.
Legionella Risk Assessment
Overall, a Legionella risk assessment is essential for ensuring the safety of individuals who may come into contact with contaminated water systems. By identifying potential sources of bacteria and implementing appropriate control measures, the risk of Legionella bacteria growth and spread can be minimized.
Guide to Compliance: Keeping Properties Safe and Meeting Legal Obligations
Legionella FAQs
Q: At what temperature is legionella bacteria most active?
A: Legionella bacteria thrive at temperatures between 20°C and 45°C, with optimal growth occurring at temperatures between 35°C and 45°C.
Q: Can a plumber do a Legionella risk assessment?
A: In most cases, a plumber is not qualified to conduct a Legionella risk assessment. Only a trained and competent Legionella risk assessor should carry out such an assessment. A plumber can perform a Legionella risk assessment if they have received the necessary training and qualifications.
Q: Can Legionella grow in bottled water?
A: Yes, Legionella bacteria can grow in bottled water, especially if it is stored at temperatures between 20°C and 45°C.
Q: Do you test hot or cold water for Legionella?
A: Both hot and cold water systems should be tested for Legionella bacteria, as they can be present in both.
Q: Does boiling water get rid of Legionella?
A: Boiling water at a temperature of 100°C for one minute can kill Legionella bacteria but it is not always practical for disinfecting large water systems.
Q: Does chlorine get rid of Legionella?
A: Yes, chlorine can be used to control Legionella bacteria in water systems, but the concentration and duration of exposure must be carefully controlled.
Q: Does COSHH cover Legionella?
A: Yes, the Control of Substances Hazardous to Health (COSHH) regulations cover Legionella bacteria, and employers must take appropriate measures to control the risk of exposure.
Q: Does water with Legionella smell?
A: No, water contaminated with Legionella bacteria does not typically have a distinctive smell or taste.
Q: How can you tell if you have Legionella in water?
A: The only way to determine if Legionella bacteria are present in water is by testing a sample in a laboratory or via portable testing equipment.
Q: How common is Legionnaires UK?
A: In the UK, there are around 200-250 cases of Legionnaires’ disease reported each year.
Q: How do I test my water for Legionella?
A: Water samples can be tested for Legionella bacteria by a laboratory that specializes in water testing.
Q: How long should you run water for Legionella?
A: To flush out water systems and minimize the risk of Legionella bacteria growth, hot water taps should be run for at least two minutes and cold water taps for at least 30 seconds.
Q: How long should you run water to prevent Legionella?
A: Running water regularly can help prevent Legionella bacteria growth, and hot water taps should be run at least once a week for two minutes, and cold water taps at least once a week for 30 seconds.
Q: How long to run taps for Legionella flushing?
A: To flush out water systems and minimize the risk of Legionella bacteria growth, hot water taps should be run for at least two minutes and cold water taps for at least 30 seconds.
Q: How often do you need a Legionella risk assessment?
A: Legionella risk assessments should be conducted regularly, and the frequency depends on factors like the complexity of the water system and the risk of exposure. A minimum of every two years is recommended.
