Legionella risk assessment checklist

Updated 16 August 2026

This checklist walks through every item that a suitable and sufficient legionella risk assessment should cover. It is drawn from ACOP L8 paragraphs 40 to 67 and HSG274 Part 2. Tick off each item as you work through your premises. For most buildings you can complete this with your own team; for care homes, hospitals, and premises with cooling towers, use it as a cross-check against what your contractor has produced.

For a Word template you can fill in, see our free legionella risk assessment template.

1. Premises and duty holder

• Premises name and address recorded
• Name and contact details of the duty holder (the employer, landlord, or person in control of the premises)
• Name of the responsible person appointed under ACOP L8, with evidence of their training and competence
• Date of the assessment
• Date of the next scheduled review (normally 12 months, or 6 months for higher-risk premises)
• Name and competence evidence of the person carrying out the assessment

2. Water system description

• Mains water supplier identified
• Location of the boundary stop tap and isolation points
• Location and capacity of every cold water storage tank
• Location, capacity, and operating temperature of every calorifier or hot water storage vessel
• Plant room and riser layout mapped
• Hot and cold water distribution routes identified
• Every outlet identified on a plan or schematic, with a unique reference number
• Any point-of-use water heaters, undersink heaters, or instantaneous heaters identified
• Any thermostatic mixing valves (TMVs) identified, with type and servicing history
• Any water softeners, filters, or treatment plant identified
• Schematic diagram drawn or updated

3. Higher-risk features

• Any cooling tower or evaporative condenser identified (notify local authority under 1992 Regulations)
• Any spa pool, hot tub, or hydrotherapy pool identified (HSG274 Part 3)
• Any humidifier, air washer, or evaporative humidification in the HVAC system
• Any fire sprinkler system or hose reel
• Any emergency shower or eye wash station
• Any fountain or water feature generating aerosol
• Any industrial process water system
• Dental unit waterlines (for dental practices)
• Endoscope decontamination water (for healthcare)

4. Temperature check during the assessment

• Calorifier flow temperature measured (target 60°C+)
• Calorifier return temperature measured (target 50°C+)
• Cold water storage tank temperature measured (target below 20°C)
• Hot water temperature measured at every outlet after one minute running (target 50°C+)
• Cold water temperature measured at every outlet after two minutes running (target below 20°C)
• Any TMV outlet blend temperature recorded
• Variations from target temperatures recorded with outlet reference number

5. Risk identification at each outlet

• Usage frequency recorded: daily, weekly, less than weekly
• Aerosol generation noted (showers and spray taps are higher risk)
• Any dead legs identified and measured
• Any capped branches or redundant pipework identified
• Any disused outlets identified (recommend removal or regular flushing)
• Condition of shower heads and flexible hoses noted
• Any limescale build-up noted
• Condition of tank lids, insulation, and screens noted

6. People at risk

• Employees identified
• Tenants, residents, patients, or visitors identified
• Any vulnerable groups identified (over 65, immunocompromised, chronic respiratory conditions, young children)
• Exposure pathways identified at each risk outlet

7. Written scheme of control

• Monthly temperature monitoring schedule at sentinel outlets defined
• Annual full-system temperature check defined
• Six-monthly cold water storage tank inspection scheduled
• Annual calorifier inspection and desludge scheduled
• Six-monthly shower head descale and disinfection scheduled
• Quarterly TMV inspection scheduled (where fitted)
• Weekly flushing programme for outlets used less than once a week, with named responsible individual
• Sampling schedule defined (where applicable)
• Procedure for shutdowns and restart defined
• Procedure for a positive sample or action threshold exceedance defined
• Procedure for notification and cooperation with health protection team in the event of a case linked to the premises

8. Records

• Legionella compliance file established (paper or electronic)
• Templates prepared for the monthly monitoring log
• Templates prepared for the flushing log
• Retention period set (minimum five years under ACOP L8)
• Backup arrangements for electronic records
• Access arrangements so records can be produced on request to HSE, CQC, or another inspector

9. Review

• Next scheduled review date recorded
• Triggers for interim review recorded (system change, occupancy change, positive sample, outbreak, new guidance)
• Sign-off by duty holder recorded
• Copy lodged with the managing agent or landlord if relevant

10. Training

• Responsible person has completed responsible person training
• Staff carrying out monitoring have completed training appropriate to their role
• Any contractor providing monitoring or remedial work is Legionella Control Association registered
• Training records held in the compliance file
• Refresher training scheduled at least every two years