Refurbishment can change the way a building’s water system behaves. Bathrooms may be relocated, outlets removed, pipework extended, temporary supplies installed or whole areas isolated for weeks. Even when the finished installation looks new, the work can introduce stagnation or leave behind redundant sections that affect Legionella risk.
Why refurbishment deserves specific attention
HSE construction guidance highlights refurbishment and demolition as activities where Legionella exposure can arise, particularly where water is stored, stagnant or recirculated and where aerosols may be produced. The risk can exist during the work as well as after handover if the modified system has not been properly reviewed.
Common post-refurbishment issues
- Dead legs or blind ends. Removed fixtures can leave redundant pipework containing stagnant water.
- Long new pipe runs. Extensions to bathrooms, kitchens or commercial units can change temperature and water turnover.
- Temporary shutdowns. Parts of the system may have remained unused while building work was underway.
- Heat gain. New service routes can place cold-water pipework beside hot services or poorly insulated plant.
- New thermostatic mixing valves. These need to be considered within the wider temperature-control strategy.
- Construction debris. Scale, sediment and contamination can affect water quality if commissioning and cleaning are inadequate.
- Changed occupancy. A conversion from office to residential, or from one large unit to several smaller units, can fundamentally alter usage patterns.
What should happen before normal occupation?
The responsible person should confirm that the risk assessment still reflects the modified building. Drawings and asset records should be updated, new outlets identified, redundant pipework removed where appropriate, and the control scheme adjusted to match the new system.
Commissioning should also verify that the system performs as intended. That can include checking temperatures, flow, cleanliness, storage conditions and the operation of recirculating systems. If disinfection or sampling is required, it should be specified according to the nature of the work, the system and competent advice rather than applied as a generic substitute for proper commissioning.
When a formal review is especially important
A review is particularly important after major plumbing changes, conversion of building use, replacement of central plant, installation or removal of water storage, new showers, prolonged shutdown or evidence that existing control parameters are no longer being achieved.
Keep the handover information
Water-safety management becomes difficult when facilities teams inherit a refurbished building without accurate drawings, commissioning records or details of isolated pipework. Handover documents should therefore become part of the ongoing water-safety file rather than being left only with the construction team.
If parts of the building were vacant during the works, see our guide to reoccupation after extended vacancy.
Official guidance: Health and Safety Executive (HSE) L8 Approved Code of Practice and HSG274 Part 2.
Post-refurbishment assessment in London: London Legionella Water Survey can review altered hot and cold water systems and identify whether the existing risk assessment and control scheme remain suitable.