L8 scope
HSE ACOP L8 covers the control of Legionella bacteria in water systems. For commercial offices, key systems include:
- Domestic hot and cold water services
- Cooling towers and evaporative condensers
- Humidifiers and spa/shower systems
- Tea points and water boilers
- Little-used outlets (annex WCs, storage taps)
Required regime
- Written Legionella Risk Assessment — reviewed every 2 years or on material change
- Appointed Responsible Person
- Monthly temperature monitoring at sentinel outlets
- Quarterly flushing of little-used outlets
- Monthly descaling of showerheads and aerators
- Annual thermostatic mixing valve (TMV) servicing
- Annual tank inspection and disinfection where applicable
Temperature controls
- Cold water: below 20°C at all outlets within 2 minutes of running
- Hot water: above 50°C at outlets within 1 minute of running
- Storage: below 20°C (cold) / above 60°C (hot)
- TMV outlets: 38–41°C at blended outlet
Common failures
- Dead-legs in pipework from tenant alterations (temperature compromised)
- Little-used outlets not flushed (high-risk biofilm growth)
- Showers used infrequently — rapid colonisation
- Tea-point supplies with long pipe runs
- Missing Legionella Risk Assessment (simple strict-liability offence)
What we do
L8 compliance integral to commercial maintenance contracts. In-house water hygiene team. See Commercial Maintenance, Office Maintenance.
FAQs
Who's the Responsible Person?
The duty-holder of the premises — landlord for common parts, tenant for demise. Both may appoint competent persons.
Is L8 testing mandatory?
Legionella testing (sampling) is not statutorily required; monitoring (temperature, visual) is. Sampling advised where control regime fails or investigation is triggered.
Need commercial expertise on this?
Measured survey and fixed-price quote within 10 working days.