The handover gap
A new building’s water system is at its most vulnerable in the weeks around practical completion. It has been filled, flushed, tested and — frequently — left to sit while snagging drags on and occupation slips. That standing water is a Legionella risk, and at exactly this moment it’s unclear who is managing it.
The contractor thinks the duty has passed to the client. The client assumes the contractor is still covering it until they move in. In the gap between those two assumptions, nobody is flushing the system.
What the duty actually requires
Under ACOP L8, the duty to control Legionella risk sits with whoever has control of the premises. Around handover that responsibility moves — but the water system doesn’t pause to wait for the paperwork. From the moment it holds water, it needs managing.
The clean answer is to agree, in writing and before completion, who is responsible for flushing and monitoring during the handover window. It is a small conversation that closes a serious gap.
The records a client should insist on
A client taking on a building should not sign for the water systems without the evidence pack: the pre-commission cleaning and flushing records, the chlorination certificate, the system schematics with asset register, and a Legionella risk assessment for the building as built.
Without those, the new responsible person is starting blind — no baseline, no asset list, no proof the system was ever cleaned. That is a poor and entirely avoidable position to inherit.
Closing the gap before completion
Bake water hygiene into the handover plan rather than treating it as an afterthought. Name the responsible person early, keep the system flushed right up to occupation, and hand over a complete evidence pack on day one.
It protects building users, it protects the client, and it protects the contractor’s position too. Everybody benefits from the duty being explicit instead of assumed.