Legionnaires’ disease is a serious, sometimes fatal pneumonia caught by inhaling water droplets contaminated with legionella bacteria. Outbreaks trace back to poorly managed water systems, cooling towers, hot and cold water services, spa pools, even garden centre misters. And in the eyes of the law, almost every employer, landlord and building operator in the UK has duties to prevent them.
The legal framework
There is no single “Legionella Act”. The duties flow from the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health Regulations 2002 (COSHH), interpreted through the HSE’s Approved Code of Practice L8, Legionnaires’ disease: the control of legionella bacteria in water systems, and the technical guidance in HSG274. An ACOP has special legal status: if you haven’t followed it, a court will expect you to prove you achieved compliance some other way.
The duties apply to employers, those in control of premises, and landlords, including residential landlords, who must assess legionella risk in their rental properties.
What ACOP L8 expects
- Risk assessment, identify whether your water systems could create legionella risk: water stored or recirculated between 20°C and 45°C, sources of nutrients (rust, sludge, scale, biofilm), means of creating breathable droplets, and exposure of susceptible people.
- A named responsible person, someone appointed to take day-to-day responsibility for controlling legionella risk, with sufficient authority, competence and knowledge of the systems.
- A written control scheme, what the system is, how risk is controlled (temperature regimes, flushing, disinfection), and how controls are monitored.
- Monitoring and records, temperature checks, flushing of little-used outlets, calorifier inspections, showerhead cleaning, and records kept of all of it.
- Review, whenever the system or its use changes, and periodically in any case.
The competence gap
Most organisations don’t fail on intent, they fail on competence. A caretaker or facilities administrator gets “legionella” added to their duties with no training, the temperature log gets filled in mechanically (or optimistically), dead legs accumulate as buildings are altered, and nobody has ever reviewed the risk assessment. When the HSE investigates a case of Legionnaires’ disease, the first questions are: who was your responsible person, and what training did they have? Prosecutions for legionella failures regularly end in six- and seven-figure fines.
ACOP L8 is explicit that the responsible person must be competent, trained to understand the systems they manage and the significance of the checks they perform.
Training the responsible person
Our online Legionella Responsible Person Training course covers the bacteria and the disease, the full legal framework (HSWA, COSHH, ACOP L8, HSG274), risk assessment, hot and cold water system controls, monitoring regimes and record-keeping, everything a newly appointed responsible person needs to run a defensible control scheme. It’s completed online at your own pace with a certificate on completion.
It sits naturally alongside our other premises-compliance training, such as Fire Risk Assessment for the Responsible Person, because in most organisations, the same people carry both duties.


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