Dental chairs have a water line unit that is used for the irrigation and cooling process when drilling etc. Whilst the majority of practices have a disinfection procedure in place this can be defeated by biofilm, resulting in high bacteria numbers building up in the dental water lines.

These high bacteria numbers can cause significant health risks such as occupational asthma and can contribute to the risk of Legionnaires Disease by providing a safe harbour for the Legionella bacteria. Dental water lines have been attributed to outbreaks of Legionella in the past and as the water line produces an aerosol in use there is the presence of a significant risk.

As such it is sensible to routinely test dental water lines to ensure they remain clean and contamination free.


Control of Substances Hazardous to Health Regulation (2002)
Health and Safety at Work Act 1974
Health and Social Care Act 2008 (Regulated Activities) Regulations 2014: Regulation 12

Professional Guidelines:

HSE – Legionnaires Disease Guide for Employers
HTM 04-01 (The Control of Legionella, Hygiene, ‘Safe’ Hot Water, Cold Water and Drinking Water Systems)
HTM 01-05 (Decontamination in Primary Care Dental Practices)
ACOP L8 (The Control of Legionella Bacteria in Water Systems)
Care Quality Commission (Registration) Regulations 2009