Do I need a legionella risk assessment?
Health and safety law requires dutyholders to assess foreseeable exposure to legionella and control the risk. The assessment can be simple for a low-risk system, but the duty does not disappear because no certificate or fixed testing interval is specified.
Check my situationUse the water and exposure test
A legionella assessment is relevant when an undertaking or premises includes a water system that can support bacterial growth and release droplets people can inhale. Stored or recirculating water, showers, low-use outlets, cooling towers and susceptible users strengthen the need for specialist input.
- Do you employ people, control premises or manage rented accommodation with a water system?
- Can water be stored, recirculated, stagnate or sit within temperatures that permit growth?
- Can the system release spray or droplets to employees, tenants, visitors or the public?
What to do next: Document the water-system boundary and responsible people even where the initial conclusion is low risk. If the system is complex or the controls are uncertain, appoint someone with relevant water-system competence.
Commercial and public premises
Offices, factories, shops, schools, hotels, care settings, leisure facilities and public buildings contain hot and cold systems of different complexity. The assessment must reflect their assets and users.
A small mains-fed system can justify simple controls. Stored water, many outlets, mixed temperatures and vulnerable people require a more detailed assessment.
Landlord duties
HSE states that landlords have duties to assess and control legionella risk. It also explains that most rented domestic hot and cold systems are low risk and do not require elaborate testing arrangements.
- Identify foreseeable risk
- Remove redundant pipework where practical
- Maintain temperature and turnover controls
- Inform tenants about control measures
Assessment review
Review the assessment when there is reason to think it is no longer valid. Changes to the system, use, occupancy, responsible people or control performance can trigger review.
ACOP L8 does not create one universal two-year certificate expiry for every system. The review timing should follow the assessment, system changes and evidence that controls remain effective.