---
title: "Managing Legionella in schools and universities"
source_url: https://legionella.io/articles/managing-legionella-in-schools-and-universities/
canonical_url: https://legionella.io/articles/managing-legionella-in-schools-and-universities/
pillar: "Building Types & Use Cases"
summary: "School and university water systems sit idle for weeks at a time. Compare holiday flushing, drain-down and rationalising outlets to keep Legionella controlled."
primary_keyword: "school Legionella"
date_published: 2025-05-20
date_reviewed: 2026-06-26
author: "Legionella.io editorial team (REMOTE TECH LTD)"
reviewed_against: "HSE L8 and HSG274 guidance"
region: "United Kingdom"
license: "(c) REMOTE TECH LTD. Quote freely with attribution and a link to source_url."
---

# Managing Legionella in schools and universities

A secondary school is empty for something like thirteen weeks a year. A university hall of residence can stand mostly unused from June to September. For most of that time the water systems stay full, warm in patches, and completely still, which is exactly the condition Legionella needs to multiply. The defining question for a school or university estate is not how to run controls during term. It is what you do with the pipework while nobody is there.

That decision repeats every holiday across a mix of buildings most other sites never have to think about: science labs with emergency safety showers, sports blocks with banks of changing-room showers, swimming pools, accommodation full of low-use ensuite bathrooms, and the odd portacabin classroom hanging off a forty-metre pipe run. Get the shutdown approach right and term-time control is almost routine. Get it wrong and the first week back becomes a gamble taken with several hundred people in the building.

## The real decision: what to do over the holidays

When a building empties, you have a small set of genuine choices, and they pull against each other. You can keep water moving by flushing through the break. You can take the water out of the parts you can safely drain. You can shrink the problem permanently by removing outlets you never use. Or you can leave it and deal with it on the way back in. Each is defensible somewhere on a real estate. The mistake is stamping one blanket policy across the whole site.

Why it matters comes down to two mechanisms. Legionella thrives in still water roughly in the 20-45°C band, so the standard defence is to keep cold water genuinely cold, keep stored hot water hot, and keep all of it moving [1]. And people only get ill when contaminated water is breathed in as a fine mist [2], which is why the showers in changing rooms and halls, not the drinking-water taps, are where school risk concentrates. A long holiday attacks the first mechanism directly: water that nobody draws goes tepid and stagnant. Stagnation is the root cause behind most of what follows, and it is worth understanding on its own terms (see [Neglected water systems](https://legionella.io/articles/neglected-water-systems-the-danger-of-stagnation/)).

## What to judge each option on

Before comparing approaches, fix the axes you will judge them by. Four matter on a school estate:

- **Stagnation control through the break** — does the approach actually stop warm water sitting still, everywhere it could?
- **Access and staff time required** — flushing every outlet weekly through August means someone is on site, with keys, doing it and recording it.
- **Recommissioning burden** — the more you take offline, the more work and risk there is in bringing it safely back before pupils return.
- **The evidence it leaves behind** — whatever you choose has to produce records a competent person, and an inspector, can read later.

How often you flush, and which outlets, is not a number you read off a chart. It follows the site risk assessment, which weighs the building, its outlets and its use pattern [3]. The comparison below is about which strategy fits, not how frequently to run it.

## Comparing the holiday options

| Approach | Best suited to | Access and effort over the break | Main risk to manage |
| --- | --- | --- | --- |
| Holiday flushing programme (run representative outlets on a set rota) | Buildings that must be ready at short notice, or that can't be drained cleanly | High — staff on site repeatedly, every flush logged | A missed week or a skipped wing leaves a stagnant pocket that looks controlled on paper |
| Partial drain-down (take seasonal or isolatable areas out of use) | Discrete blocks you can isolate — a closed sports hall, a vacated hall of residence wing | Lower mid-break, but heavy at both ends | Residual water and damp left behind; getting recommissioning wrong on return |
| Rationalising the estate (cap dead legs, remove outlets you never use) | Any site carrying redundant taps, showers and blind pipe runs | One-off effort, then permanently less to manage | Needs a competent survey so a "redundant" outlet isn't quietly someone's only supply |
| Pre-reopening blitz only (leave it, then clean, flush and check before return) | Short closures, or as a backstop layered on top of the others | Concentrated into the days before reopening | Over a six-week summer this alone is rarely enough; one busy week back can undo a rushed flush |

No single row wins outright, which is the point. Most well-run estates blend them: rationalise once to cut the permanent burden, drain down what can be isolated, flush what stays live, and treat a thorough pre-reopening check as the final gate rather than the whole plan.

## Which to pick where

A small primary school with one boiler, short pipe runs and a caretaker who knows every valve can often run a straightforward holiday flushing programme and a careful return. The estate is small enough to hold in one person's head, and a sensible rota covers it.

A multi-academy trust is a different shape. The duty sits at trust level across a dozen sites with patchy plant records, so the win is usually rationalising first, then a consistent flushing rota each site can actually staff. Spreading one team thinly across many buildings is precisely how a wing gets missed.

A university campus is the hardest case, because "empty" is rarely true. Halls of residence that look vacant over summer are frequently let for conferences and summer schools, which means partial occupancy in unpredictable blocks. Treat any occupied corridor as in use and flush it, rather than assuming a quiet building is a dormant one. Sports and leisure facilities add their own wrinkle: a spa pool or hot tub in a university gym is a recognised higher-risk system that sits under its own guidance, separate from the hot-and-cold rules covering the rest of the estate [4]. Science blocks bring emergency safety showers and eyewash stations, which exist to be used in an instant and almost never are; left unflushed, the very fittings meant to protect lab users become a reservoir.

## Before you commit to any of them

None of the above replaces your own risk assessment. The figures that actually govern a school estate — which outlets, how often, what counts as in range, when to escalate — come from a competent, site-specific assessment of your buildings and your users, not from a comparison table. Children, and on a campus the occasional immunocompromised resident, are part of who you are protecting, so the bar for "good enough" is set deliberately, in writing, by someone qualified to set it. Use the options here to frame the holiday conversation, then have that person confirm what each of your sites genuinely needs.

## FAQ

### Do we really have to flush the whole school every week of the summer holidays?
Not necessarily the whole school, and not necessarily weekly. The right frequency and the right list of outlets come from your risk assessment, which is allowed to treat a capped, drained or genuinely isolated area differently from a live one [3]. What you cannot do is assume an empty building is a safe one and skip the question entirely.

### In an academy trust, is the school or the trust the duty holder?
The legal responsibility for managing the risk rests with the organisation in control of the premises, and outsourcing tasks to a contractor does not move it [5]. In a trust that typically means the duty sits centrally, with named responsible people at each site carrying out the controls. The important thing is that the chain is written down, so no building falls between the trust and the local team.

### Do laboratory safety showers and eyewash stations count?
Yes, and they are an easy thing to forget. They are designed to deliver water rarely and instantly, so they sit unused for long stretches and can stagnate like any other low-use outlet. Include them in the flushing regime and the records, rather than treating them as safety equipment that somehow sits outside water hygiene.

## A first move for the next break

Before the next holiday, build a one-page shutdown plan per building. For each one, write down what happens to its water over the break (flushed, partly drained, isolated, or live for conferences), who does it, who recommissions it, and what gets recorded each time. That single sheet turns a vague intention to "keep on top of flushing" into something a colleague can pick up and an inspector can follow. Pair it with a tidy record-keeping system so the evidence survives the staff turnover that every estate eventually has (see [Essential records for Legionella compliance](https://legionella.io/articles/essential-records-for-legionella-compliance/)).

## Related reading

- [Neglected water systems: the danger of stagnation](https://legionella.io/articles/neglected-water-systems-the-danger-of-stagnation/)
- [Essential records for Legionella compliance](https://legionella.io/articles/essential-records-for-legionella-compliance/)
- [Legionella control in office buildings](https://legionella.io/articles/legionella-control-in-office-buildings/)
- [Legionella risks in hotels and hospitality](https://legionella.io/articles/legionella-risks-in-hotels-and-hospitality/)

## Sources

[1] HSE, "Hot and cold water systems". https://www.hse.gov.uk/legionnaires/hot-and-cold.htm
[2] CDC, "How Legionella Spreads". https://www.cdc.gov/legionella/causes/index.html
[3] HSE, "Legionnaires' disease: Technical guidance (HSG274)". https://www.hse.gov.uk/pubns/books/hsg274.htm
[4] HSE, "Control of legionella and other infectious agents in spa-pool systems (HSG282)". https://www.hse.gov.uk/pubns/books/hsg282.htm
[5] HSE, "Legionnaires' disease - what you must do". https://www.hse.gov.uk/legionnaires/what-you-must-do/index.htm