Legionella in the News: The Pre-Return Reality for Estates

Some of you might have read about the UKHSA investigating a London Legionella cluster. With eight confirmed cases, they noted the outbreak is "atypical for this point in the year." It is a stark reminder of the broader data: there were 472 confirmed cases across England and Wales in 2024.

While that investigation continues, the timing is highly relevant for education estates. Easter is days away—making this one of the highest-risk windows for school water safety.


The risk isn't when you close. It's when you open.

The assumption is often that the holiday itself is the hazard. But the actual risk is realised the morning the building reopens. That is when water that has sat at ambient temperature in dead legs, old calorifiers, and little-used outlets for two weeks starts moving through the system again.

Legionella multiplies between 20°C and 45°C. In a lightly heated school in late March, sitting water stays comfortably in that danger zone for the entire fortnight.

The gap isn't knowledge. It's confirmation.

HSG274 Part 2 is explicit: hot and cold outlets must be flushed before returning from a break. A quick run of a tap does not count; the entire supply pipework must be replenished with fresh mains water.

Most site teams know this. The breakdown happens between "this is in our policy" and "this has been logged by a named person on a specific date."

The end of term is chaotic. Systematic flushing is exactly the kind of physical task that gets mentally filed as "covered" when it was only half-finished. Under ACOP L8, a policy saying flushing will happen is not a legal defence without the hard evidence that it did.

The pre-return guidance

To comply with ACOP L8, your site team’s regime must cover:

Flush all outlets: Run all hot and cold outlets to clear dead legs. Run all showers on the hottest setting for at least two minutes.

Test on a weekly rotation: For each building, test at least two outlets per category on a weekly rotation so everything is covered over time:

Three-monthly maintenance: Remove, de-scale, disinfect, and replace all showerheads and blending valves.

Log the evidence: Record the exact identity of the outlets tested, the temperatures, any faults, and the remedial actions directly into your system to maintain a permanent audit trail.

The water will sit either way. Before the break, it is worth asking whoever manages your water systems: is the flushing and testing regime strictly recorded and rotating correctly, or is it just assumed?

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