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Understanding Legionella Testing and Water Analysis in Office Environments.

Water testing and Legionella analysis is a critical aspect of maintaining a healthy and safe environment, especially in office buildings where employees spend a significant portion of their time. One of the potential risks associated with water systems is the presence of Legionella bacteria, which can lead to Legionnaires' disease, a severe form of pneumonia. In this blog post, we will explore the importance of Legionella testing and water analysis in office environments, highlighting key considerations and best practices.

Legionella and Legionnaires' Disease:

Legionella is a type of bacteria commonly found in water sources, such as lakes and rivers. However, it becomes a concern when it proliferates in man-made water systems like cooling towers, hot water tanks, and plumbing systems. When contaminated water droplets are inhaled, individuals may contract Legionnaires' disease, which can be especially dangerous for those with weakened immune systems or underlying health conditions. Although there are common places where Legionella is found, Legionella may grow in ANY water system due to a range of reasons such as incorrect temperatures, poor management or even water stagnation.

The Role of Legionella Testing:

Legionella testing is a crucial component of a comprehensive water quality management plan in office buildings. Regular testing helps identify the presence and concentration of Legionella bacteria in water systems. By understanding the risk levels, building managers can implement effective control measures to prevent outbreaks and protect occupants as the HSE states that “If you are an employer or someone in control of the premises, including landlords you need to be aware of the risk’s legionella poses”.


The good news is that within office environments the water supply is often always in use, from the kitchen taps to the bathroom sink, this reduces the likelihood of Legionella being present. It is however required as according to the Health and safety act 1974, that you are required to protect all employees, staff and contractors and by not carrying out a Legionella Risk assessment you could run the risk of then contracting legionnaires disease if Legionella is present. HSE Guidelines advise that “Water samples should be analysed for Legionella periodically to demonstrate that bacteria counts are acceptable”.

Absolute Water compliance provide in-field accredited Legionella water testing and analysis, where trained engineers can visit your property and collect water samples, of which sample will be collected from areas highlighted in the initial Legionella Risk Assessment. At which time the water will be tested in the laboratory to test for the presence of Legionella along with the bacterial count. Legionella sampling should be “carried out where there is doubt about the efficacy of the control regime or it is known that recommended temperatures, disinfectant concentrations or other precautions are not being consistently achieved throughout the system” HSG 274 part 2

Key Considerations for Legionella Testing:

  1. Legionella Risk Assessment: Conduct a thorough risk assessment of the office water system to identify potential areas where Legionella bacteria may thrive. Factors such as water temperature, stagnation, and the presence of biofilm can contribute to bacterial growth.

  2. Sampling Protocols: Follow established sampling protocols when collecting water samples for Legionella testing. This may involve sampling from various points in the water system, including taps and cooling towers. Proper sampling ensures accurate results that reflect the overall water quality.

  3. Frequency of Testing: Establish a regular testing schedule based on the risk assessment and local regulations. High-risk environments may require more frequent testing to ensure early detection of Legionella contamination.

What Areas should be tested within an office space?

·        Drinking water

·        Hot and cold-water storage tanks

·        Water Heaters

·        Any other water systems on site

Water Analysis Beyond Legionella:

While Legionella testing is crucial, a comprehensive water analysis should go beyond just this bacterium. Consider testing for other waterborne contaminants, such as lead, copper, and microbial pathogens, to ensure a complete understanding of water quality in the office building.

Implementing Preventive Measures:

  1. Temperature Control: Maintain water temperatures within recommended ranges to discourage Legionella growth. Hot water should be stored and distributed at temperatures that inhibit bacterial proliferation, a Legionella thermometer can be used.

  2. Water System Maintenance: Regularly clean and disinfect water systems, including Cold water tanks and plumbing, to reduce the risk of bacterial colonisation. Proper maintenance helps prevent the formation of biofilm, a common breeding ground for Legionella.

  3. Educating Occupants: Raise awareness among office occupants about the importance of water hygiene and encourage reporting of any water-related issues promptly. The building manager could partake in a Legionella awareness course so that they have in depth knowledge about the requirements to remain compliant for their business.

Legionella testing and water analysis are essential components of a proactive approach to water quality management in office environments. By understanding the risks, implementing preventive measures, and conducting regular testing, building managers can create a safe and healthy workspace for employees.

Want to find out if you are compliant? Why not take a look at Absolute Water Compliance’s Free Legionella Audit, a guide to compliance, or get in contact today to discuss your requirements.


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