Legionella risk management in data centres: keeping water systems compliant and operational
Data centres are built around resilience, uptime and performance. However, alongside critical power and cooling infrastructure sits another important operational responsibility: legionella risk management.
While data centres are not traditionally viewed as high-risk environments, many facilities contain water systems capable of creating conditions where legionella bacteria can grow if systems are not correctly managed.
As cooling technologies evolve and operational demands increase, maintaining an effective water hygiene strategy has become an essential part of facilities management within the data centre sector.
Why legionella risk matters in data centres
Many modern data centres contain complex water systems that require ongoing monitoring, maintenance and control, including:
- Cooling towers and evaporative condensers
- Domestic hot and cold water systems
- Humidification systems
- Adiabatic cooling systems
- Emergency showers and eye wash stations
- Water storage tanks
- Low-use or infrequently accessed outlets in secure areas
Closed-loop chilled water systems are generally considered lower risk, particularly where systems remain genuinely sealed. However, any system involving stored, recirculated or aerosolised water can present potential legionella concerns if controls fail or maintenance standards decline.
For facilities teams, the challenge is ensuring that all systems are identified within the site’s legionella risk assessment and supported by a clear monitoring and control programme.
How data centres typically reduce legionella exposure
Many data centres already implement measures that help minimise legionella risk as part of wider operational resilience strategies, including:
- Minimising potable water systems where possible
- Using sealed or closed cooling loops
- Separating process water from domestic water systems
- Continuous Building Management System (BMS) monitoring
- Automated flushing regimes
- Specialist water treatment contracts
- Formal written control schemes and compliance logbooks
These controls can significantly reduce operational risk, but they still require regular review, verification and documentation to remain effective and compliant.
What auditors and assessors typically expect
Whether managing a live facility or preparing for an external audit, there are several key areas that organisations are expected to demonstrate:
- Current legionella risk assessments
Risk assessments should accurately reflect the current site layout, water systems, operational usage and any recent infrastructure changes.
- Written control schemes
A documented control scheme should clearly outline monitoring responsibilities, inspection frequencies, escalation procedures and corrective actions.
- Monitoring and temperature records
Routine monitoring records should demonstrate ongoing compliance with required control limits and show that issues are identified promptly.
- Corrective action tracking
Any failures, non-conformances or remedial works should be documented with evidence of completion and review.
- Flushing and cleaning records
Auditors will often request evidence of flushing regimes, tank inspections, cleaning schedules and maintenance activities.
- Competent person responsibilities
Sites should have clearly defined responsible persons and evidence that those managing water hygiene risks are suitably competent.
- Trend analysis and escalation procedures
Increasingly, organisations are expected to demonstrate proactive management through trend analysis, data review and formal escalation processes where recurring issues are identified.
Moving beyond tick-box compliance
Effective legionella management in data centres goes beyond collecting routine readings.
A robust water hygiene strategy should combine:
- Accurate and up-to-date risk assessments
- Clearly defined monitoring programmes
- Reliable record keeping
- Proactive corrective actions
- Regular review of system performance and operational changes
With uptime, compliance and operational continuity all under increasing scrutiny, water hygiene management should be viewed as a critical part of overall facility resilience — not simply a compliance exercise.
Supporting compliant and resilient data centre operations
At HBE UK, we support organisations across critical infrastructure sectors with legionella risk assessments, water hygiene monitoring and compliance support services tailored to complex operational environments.
Our team works with facilities managers, estates teams and compliance leads to help ensure water systems remain safe, compliant and aligned with operational requirements.
Is your data centre’s water management strategy keeping pace with operational demands? Get in touch