Restarting dental unit waterlines after a treatment-room closure

Water that has stood in a dental unit's narrow waterlines during a closure is a raised contamination risk. Before treating patients again, follow the practice's HTM 01-05 based protocol to flush, disinfect where indicated and check the lines, and record who confirmed the room safe to use.

What has happened

A surgery or the whole practice reopens after a closure: a holiday shutdown, refurbishment, equipment fault, staffing gap or unplanned closure. Dental unit waterlines (DUWLs) are narrow tubes prone to biofilm, and standing water raises the risk of microbial contamination such as Legionella and Pseudomonas. HTM 01-05 (Decontamination in primary care dental practices) sets the decontamination standard for primary care dentistry, including waterline management, so a reopening after non-use is a point to manage the lines, not just switch the chair back on.

Immediate actions (before treating patients)

Follow the practice's written waterline and reopening protocol, based on HTM 01-05 and the manufacturer's instructions. Flush the lines and all outlets (handpieces, three-in-one, cup filler) for the required time to draw fresh treated water through, and carry out a disinfection cycle where the closure length or protocol indicates. Where the protocol requires, take a water sample or use the practice's monitoring method before patient use. Check the water bottle/independent supply and any dosing system are correct. Only return the room to patient treatment once the responsible person confirms the lines have been managed.

What not to do

Do not treat patients on a chair whose lines have merely been switched on after a long closure, and do not skip disinfection because "it's only been a couple of weeks" without checking the protocol. Do not ignore the three-in-one and other outlets, and do not rely on mains flushing alone if your protocol requires disinfection or testing. Do not reopen without recording who confirmed the room ready.

Who is responsible

The practice's decontamination lead and the registered manager or principal dentist are responsible for the waterline and reopening protocol and for confirming the room is safe to use; the clinical team follows it. The practice's water safety/legionella arrangements sit alongside, and specialist advice supports higher-risk situations.

Evidence and records

Record the closure period, the reopening waterline procedure carried out (flush, disinfection, any sampling), the readings or results, the dosing/independent supply checks, and the sign-off confirming each surgery is safe for patient use, with the date and responsible person. Keep this with the practice's decontamination and water-safety records for CQC and HTM 01-05 evidence.

Escalation

Escalate an adverse water result or a persistent contamination problem to your water-safety adviser and follow the practice's remediation before treating patients. Where waterline issues recur or connect to other decontamination concerns, review alongside the waterline taste and odour complaint and washer-disinfector failed check processes.

Prevention

Keep a clear waterline management regime (routine flushing, disinfection schedule, monitoring), a defined reopening procedure for any closure, and manufacturer-aligned protocols, and log each surgery's checks. Building the reopening step into any planned or unplanned closure makes safe restart routine rather than something to remember under time pressure.

Where Complys can help

Complys can hold the practice's decontamination and water-safety protocols, waterline check and disinfection logs, and reopening sign-offs, keeping the evidence together for CQC and HTM 01-05. It does not manage waterlines or make clinical decontamination decisions; the decontamination lead and clinicians do. Ask the Complys team to show how decontamination checks and sign-offs are tracked.