Legionella risk assessment for Dental practices
Updated 16 August 2026
Key points
- A legionella risk assessment is required for dental practices premises under the Health and Safety at Work Act 1974 and the Approved Code of Practice L8
- Typical cost: £250 to £500
- Review every 12 months, or sooner if the water system, its use, or the people using it change
- A named duty holder (usually the employer, landlord, or building operator) must arrange it and act on its findings
Dental practices have a specific legionella risk that goes beyond the general water system: the dental chair unit waterlines that deliver water to the handpiece, air-water syringe, and ultrasonic scaler. These narrow-bore lines run at body temperature and spend most of their time standing still, which is ideal for biofilm formation and legionella colonisation. Multiple published studies have found legionella in dental unit waterlines at practices that were otherwise well-managed.
The CQC expects dental providers to comply with HTM 01-05 on decontamination and HTM 04-01 on safe water systems. The waterline management regime typically includes daily flushing at the start and end of surgery sessions, use of an approved disinfectant dosing system, weekly purging of the system, and periodic sampling. The practice water hygiene plan should cover both the building water system (the same as any commercial premises) and the dental unit waterlines as a distinct sub-system with its own controls.
Small practices can manage the duty in-house with the right training. Larger group practices and those with hydrotherapy or orthodontic water systems usually engage a specialist water hygiene contractor.
Is it legally required?
Dental practices are commercial premises under the Health and Safety at Work Act 1974 and are subject to ACOP L8 in the normal way. Additional requirements apply under CQC registration through the Health and Social Care Act 2008, with HTM 01-05 and HTM 04-01 as the technical standards. Dental unit waterline management is covered specifically in HTM 01-05 chapter 2.
Who is the duty holder?
The duty holder is whoever has control of the premises or the water system. For dental practices premises, this is usually the employer, owner, landlord, or managing agent. The duty cannot be contracted out: you can hire a water hygiene consultant, but the legal responsibility still sits with you.
If you are unsure who holds the duty for your premises, see: Who is responsible for a legionella risk assessment?
What the assessment should cover
ACOP L8 sets out five things a suitable and sufficient assessment must do:
- Identify and assess sources of risk across the whole water system, including stored hot and cold water, dead legs, rarely used outlets, and any equipment that generates aerosols
- Produce a written scheme for preventing or controlling the risk, with specific tasks, temperatures, and frequencies
- Implement, manage, and monitor the scheme in practice, not just on paper
- Keep records of the assessment, the scheme, monitoring results, and any remedial action taken
- Appoint a competent person (often called the "responsible person") to be accountable for the scheme
Free legionella risk assessment template
A structured Word document following the five-step approach in ACOP L8. Covers risk identification, written scheme, monitoring, and records. If it isn't written down, you can't evidence it.
Follows ACoP L8 and HSG274 Part 2. Free. No spam.
Specific water system risks to check
For dental practices premises, assessors typically pay close attention to:
- Hot water storage temperatures (calorifiers must reach 60°C throughout)
- Hot water distribution temperatures (50°C within one minute at outlets)
- Cold water storage tank condition, lid seal, and temperature (below 20°C)
- Dead legs, redundant pipework, and little-used outlets
- Shower heads, flexible hoses, and thermostatic mixing valves
- Any cooling tower, evaporative condenser, or spa pool (these are notifiable to the local authority under the Notification of Cooling Towers and Evaporative Condensers Regulations 1992)
How often to review
There is no fixed legal interval, but ACOP L8 requires that the assessment is reviewed regularly and whenever there is reason to believe it may no longer be valid. For most dental practices premises, that means at least every 12 months and sooner after any of the following:
- Changes to the water system (new pipework, fittings, equipment)
- Changes to the use of the building or the number of occupants
- A positive legionella test result or a case of Legionnaires' disease linked to the premises
- Prolonged periods of low occupancy or system shutdown (a risk during holidays, term breaks, or refurbishment)
- New guidance from HSE
Typical cost
A professional legionella risk assessment for dental practices premises typically costs between £250 and £500, depending on the size of the building, the number of water outlets, and whether there are any cooling towers or evaporative condensers (these add significantly to the cost because of the statutory inspection regime).
Use our cost calculator for an estimate based on your specific water system.
Need a legionella risk assessment for your premises? We will be partnering with Legionella Control Association registered providers shortly.
Free legionella risk assessment template
A structured Word document following the five-step approach in ACOP L8. Covers risk identification, written scheme, monitoring, and records. If it isn't written down, you can't evidence it.
Follows ACoP L8 and HSG274 Part 2. Free. No spam.
The dental practice template + worked example — Pro edition, £29
A completed worked example for dental practices, the editable Word and Excel documents, and the smart log book to run your monitoring from. It records, it never certifies.