Facility managers juggle countless responsibilities, from ensuring smooth operations to keeping costs in check. But one critical risk often lurks unseen in building water systems—Legionella and other waterborne bacteria.
If left unmanaged, these invisible threats can pose serious health risks, cause costly legal liabilities, and disrupt business operations.
Understanding how Legionella develops, where it hides, and how to prevent outbreaks is essential for every facility manager.
Legionella is a type of bacteria that thrives in warm water systems and, when inhaled through mist or vapour, can cause Legionnaires' disease—a severe and potentially fatal pneumonia. It can also lead to Pontiac fever, a milder flu-like illness.
This disease is not spread from person to person but through contaminated water systems, especially those with stagnant or poorly maintained water. Outbreaks have been linked to:
✔ Cooling towers
✔ Hot water tanks & heaters
✔ Showers & taps
✔ Air conditioning systems
✔ Fountains & decorative water features
✔ Spa pools & humidifiers
Legionella thrives in water temperatures between 20°C and 45°C (68°F - 113°F). If water sits stagnant in pipes, tanks, or cooling towers without proper circulation and treatment, bacteria can multiply rapidly.
Once the bacteria become airborne through fine droplets (such as steam or spray from showers or HVAC systems), they pose an inhalation risk to building occupants, particularly those with weakened immune systems, older adults, or people with respiratory conditions.
Ignoring Legionella can have severe consequences for businesses and facility managers, including:
🔴 Health & Safety Violations – Many countries have strict health and safety regulations around Legionella control. Non-compliance can lead to fines or even criminal liability.
🔴 Lawsuits & Liability – If an outbreak occurs in your facility, affected individuals may take legal action, leading to financial and reputation damage.
🔴 Operational Disruptions – If a Legionella outbreak is detected, buildings may be forced to close while investigations and remedial actions take place, leading to lost revenue and inconvenience.
❌ Do not let water stagnate in the Legionella-friendly temperature range (20°C - 45°C).
✅ Keep hot water stored at 60°C (140°F) or above and ensure it reaches all outlets at minimum 50°C (122°F).
✅ Cold water should be kept below 20°C (68°F) and circulated properly.
🔄 Stagnant water creates an ideal environment for Legionella. If taps, showers, or outlets are unused for a week or more, they should be flushed with hot water for at least two minutes.
🛑 Cooling towers should be regularly cleaned, disinfected, and chemically treated to prevent bacterial growth.
🌀 Air conditioning systems with water reservoirs should also be inspected and maintained to prevent bacterial spread.
💧 Consider using chlorination, UV disinfection, or other water treatment methods to kill bacteria in your system.
🔬 Regularly test water quality to monitor bacterial levels and detect issues before they escalate.
📋 Legionella risk assessments should be carried out at least annually or whenever significant changes occur in the water system.
⚠ Compliance with local regulations (such as the UK’s ACOP L8 or local building codes) is essential to avoid legal risks.
Facilities management teams, maintenance staff, and cleaning crews should be trained to recognise Legionella risks and follow best practices in water system maintenance.
If your facility has any of the following risk factors, it’s time to take action:
✅ Large, complex water systems (hospitals, hotels, office buildings, shopping centres)
✅ Water storage tanks or cooling towers
✅ Long pipe runs or dead-end plumbing lines
✅ Low-usage areas with stagnant water (vacant floors, seasonal buildings)
✅ Old or poorly maintained plumbing systems
Legionella prevention is not just a regulatory requirement—it’s a critical safety measure that protects employees, customers, and the public.
At Pleasant Plumbers, we specialise in Legionella risk assessments, water treatment solutions, and preventative maintenance to keep your building safe and compliant.
Call us or WhatsApp us on 0800 046 1000 to ensure safety and peace of mind today.