DynamoDental

Health and Safety at Work etc. Act 1974; Control of Substances Hazardous to Health Regulations 2002; HSE Approved Code of Practice L8 (Legionnaires' disease: the control of legionella bacteria in water systems)

Legionella and water-safety controls for dental unit waterlines

Legionella bacteria can grow in water systems where water is stored or stagnant and temperatures sit between roughly 20°C and 45°C. Employers and those in control of premises have a duty under the Health and Safety at Work Act and COSHH to assess and control the risk. HSE's Approved Code of Practice L8 and the technical guidance in HSG274 set out what is expected: a risk assessment by a competent person, a written scheme of control, monitoring and records.

Jurisdiction
England
Last verified
9 September 2026
Next review
9 March 2027
Version
1

In plain English

Legionella bacteria can grow in water systems where water is stored or stagnant and temperatures sit between roughly 20°C and 45°C. Employers and those in control of premises have a duty under the Health and Safety at Work Act and COSHH to assess and control the risk. HSE's Approved Code of Practice L8 and the technical guidance in HSG274 set out what is expected: a risk assessment by a competent person, a written scheme of control, monitoring and records.

In a dental practice the risk covers the building's hot and cold water systems, and also the dental unit waterlines that carry water to handpieces and the three-in-one syringe. Waterlines are narrow-bore tubing with intermittent flow, which is why HTM 01-05 gives separate guidance on managing them.

Dynamo Dental maintains the chair's waterline hardware. Assessing the risk and deciding the control measures for the practice is the practice's duty, carried out with a competent water-safety assessor.

Who does what

Your responsibility as the provider

  • Arranging a Legionella risk assessment of the premises' water systems by a competent person, and reviewing it when circumstances change or at the interval the assessor recommends
  • Appointing a responsible person for water safety
  • Implementing the written scheme of control: temperature checks, flushing of infrequently used outlets, cleaning and descaling, and any treatment the assessment calls for
  • Managing dental unit waterlines in line with HTM 01-05 and the chair manufacturer's instructions
  • Keeping monitoring records and acting on results
  • Making sure contractors who work on water systems are competent

What Dynamo Dental delivers directly

  • Servicing and repairing the treatment unit's water system components (independent reservoirs, filters, valves, anti-retraction devices, cuspidor supply) to the manufacturer's instructions
  • Installing chairs with an independent water reservoir where the practice's water policy requires it, and recording how each unit is fed
  • Recording the water source and waterline arrangement of each chair on the asset register, which the water-safety assessor will need
  • Noting any observed concerns with the chair's water system (for example a unit fed directly from the mains where the practice believed it was bottle-fed) and reporting them

Verified specialist competence, or a specialist partner

  • Legionella risk assessment and the written scheme of control: a competent water-safety assessor
  • Water sampling and laboratory testing, including of dental unit waterline output: a laboratory or water specialist
  • Work on the building's hot and cold water systems, storage tanks, calorifiers and pipework: a competent plumbing or water-treatment contractor
  • Selection of waterline treatment products: the practice's decontamination lead, following the chair manufacturer's guidance on compatibility

Outside our scope

  • Legionella risk assessments
  • Water sampling or testing
  • Plumbing and building water-system work
  • Certifying water safety

Questions

Questions on this topic

Does a chair service cover Legionella?

No. A chair service maintains the chair's water hardware to the manufacturer's instructions. Legionella control is a duty on the practice, met through a risk assessment by a competent assessor, a written scheme of control and monitoring. The service report shows the waterline components were maintained; it is not evidence that the water system risk has been assessed or controlled.

Should our chairs be fed from the mains or from a bottle?

That depends on the chair's design, the manufacturer's instructions, the practice's water policy and the risk assessment. Many units use an independent reservoir so that treated water can be used and backflow into the mains is avoided. We install and maintain whichever arrangement the practice and its assessor have decided on, and record it.

Other topics

Not sure what records you should have?

The Practice Engineering Survey establishes what exists and what is missing, without claiming to be an audit.

Report a problem Get a servicing quote