The shift to hybrid working has transformed offices across the UK. While reduced occupancy brings flexibility and cost savings, it also creates a hidden health hazard: stagnant water systems that increase the risk of Legionella growth. Without proper Legionella risk management, businesses could face serious legal, financial, and reputational consequences.
Why hybrid working increases Legionella risks
Legionella bacteria thrive in stagnant or slow-moving water, particularly at temperatures between 20°C and 45°C. In buildings with reduced occupancy, taps, showers, and pipework may go unused for days or weeks. This allows water to sit in the system, creating the perfect environment for bacterial growth.
If inhaled via water droplets — for example, from showers, air conditioning systems, or cooling towers — Legionella can cause Legionnaires’ disease, a potentially fatal form of pneumonia.
Updated HSE guidance for Legionella risk management
The Health and Safety Executive (HSE) has reinforced its guidance for employers and building managers, with particular focus on:
Regular flushing regimes
Flush all outlets at least weekly to prevent stagnation.
Ensure hot water reaches at least 60°C and cold water stays below 20°C.
Monitoring and record keeping
Regularly test water temperatures and system performance.
Keep detailed logs to demonstrate compliance.
Risk assessments
Review and update your Legionella risk assessment whenever building usage changes.
Identify high-risk outlets and take corrective action.
Maintenance of water systems
Descale showerheads and taps quarterly.
Inspect and maintain tanks, cooling towers, and other water storage systems.
Real-world lessons
In 2023, a UK office building partially closed for refurbishment experienced a Legionella outbreak due to insufficient flushing during reduced occupancy. The incident led to temporary closure, costly remediation, and reputational damage — all of which could have been avoided through proactive Legionella risk management.
Prevention tips for hybrid workplaces
Implement an automated flushing schedule for underused outlets.
Train staff on recognising Legionella risks and reporting maintenance issues.
Coordinate with water hygiene specialists for regular inspections and testing.
Ensure all maintenance records are easily accessible for audits or HSE inspections.
The legal duty is clear
Under the Health and Safety at Work etc. Act 1974 and Control of Substances Hazardous to Health (COSHH) regulations, employers and those in control of premises have a legal duty to manage Legionella risks. Ignoring this responsibility can result in prosecution, fines, or imprisonment.
Final word
Hybrid working is here to stay — and so is the need for robust Legionella risk management. By following updated HSE guidance, reviewing risk assessments, and maintaining proactive flushing and monitoring schedules, businesses can protect their people, remain compliant, and avoid costly incidents.
If you need any assistance with your legionella risk assessment or workplace safety services, please get in touch. One of our compliance experts will be happy to assist you.
