Office Lgionella Why 'Low Occupancy' Is High Risk

Many UK office buildings across the UK now sit partially unoccupied for days or even weeks at a time. The result? Stagnant water in taps, showers, and HVAC systems. All of which were originally designed for full-time use.

In June 2025, the BBC reported a growing concern around the rise of Legionella detections in office environments. Especially so in older buildings and business centres with inconsistent use.

This trend presents a very real health and compliance risk for:
- Landlords of serviced offices
- Commercial property managers
- Facilities teams overseeing multi-tenant workspaces

Why Part-Time Buildings Are Full-Time Risks

Legionella bacteria flourish in warm, standing water. When outlets go unused, particularly in older or decentralised plumbing systems. Bacteria has more time to grow.

Common risk areas include:
- Kitchenettes with unused boiling taps
- Showers in vacant changing rooms
- Staff toilets in low-traffic zones
- Water features or decorative fountains
- Backup water heaters and redundant tanks

These aren’t just theoretical risks. Several UK offices have already reported staff illness and failed inspections linked to dormant water systems.

Compliance Responsibilities for Commercial Landlords

Under the HSE’s ACoP L8 guidance. All landlords and responsible persons must regularly assess and manage Legionella risk. This is regardless of building occupancy.

Failing to do so could result in:
- Legal action if illness occurs
- Insurance complications
- Failed HSE audits
- Tenant disputes and void periods

The shift to flexible work patterns has not changed your compliance duties.

Practical Prevention: HSRA’s Office Legionella Checklist

Before any period of reoccupation or tenant handover, we recommend running through this basic compliance list:

10 Things to Flush, Test or Replace:
1. Dead legs in pipework
2. Unused taps and showers
3. Tea points and breakroom boilers
4. TMVs (thermostatic mixing valves)
5. Calorifiers and storage tanks
6. HVAC humidifiers
7. Emergency eye-wash stations
8. Shower heads and hoses
9. Drinking fountains
10. Water testing records

Your Risk, Our Responsibility

HSRA works with managing agents, office landlords, and serviced workspace providers to deliver:
- Legionella risk assessments
- Routine flushing plans
- Testing kits and water sampling
- Compliance documentation for audit readiness

Let us help you keep your building healthy, even when it’s only half full.

Book your office water risk review today.