---
title: "Legionella in warehouses, distribution centres and cold stores"
source_url: https://legionella.io/articles/warehouse-distribution-centre-legionella/
canonical_url: https://legionella.io/articles/warehouse-distribution-centre-legionella/
pillar: "Building Types & Use Cases"
summary: "Warehouses use little water but hold large static tanks. How to control Legionella in welfare blocks, cold stores and sprinkler tanks across many sites."
primary_keyword: "warehouse Legionella"
date_published: 2026-05-11
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."
---

# Legionella in warehouses, distribution centres and cold stores

A warehouse's biggest Legionella risk is not what it stores or ships — it is how little water the building uses. Hundreds of thousands of square feet, a skeleton crew, and pipework and tanks sized for a workforce that has long since shrunk add up to one thing: water sitting still, warming up, and feeding bacteria in the few places people actually breathe it in.

That makes the warehouse risk profile genuinely different from the heavy-industry one. A factory's hazard is often the process itself — cooling towers, evaporative kit, wash plant — covered in [Legionella prevention in industrial facilities](https://legionella.io/articles/legionella-prevention-in-industrial-facilities/). A distribution shed usually has none of that. Its hazard is stagnation in a small welfare block bolted onto an enormous, near-empty box, plus large volumes of static stored water that nobody disturbs from one quarter to the next.

## Why an empty building is the hazard

Legionella multiplies in warm, still water and reaches people as a fine aerosol — a shower spray, a tap splash, a hose mist [4]. The HSE lists infrequently used outlets and stored or recirculated water among the systems most likely to create risk [2]. A 3PL distribution centre stacks both problems at once.

Think about the numbers in your own building. The cold water storage tank was specified for the original design occupancy or sprinkler demand, not for the dozen people on shift today. Turnover in that tank is slow, so the water warms toward room temperature and can drift above the temperatures your scheme relies on [3]. The hot water loop serves a couple of toilet cores down one elevation, leaving long runs that cool into the danger zone. And half the outlets — the second-floor shower, the goods-in WC, the eyewash by the battery bay — go days or weeks without use.

None of this is exotic. It is the ordinary physics of a big building with tiny demand, and it is exactly what your risk assessment under the ACoP L8 framework has to grapple with [1].

## The welfare block: where the people and the aerosols are

Control effort should concentrate here, because the welfare core is the only part of the site that routinely makes breathable spray close to a human being.

Walk it and you will usually find showers plumbed in for the first-aid or decontamination case and used almost never; a kitchenette tap; WCs split between a busy ground-floor bank and near-dormant upstairs ones; and safety showers or eyewash stations near charging areas and decant lines. Each unused outlet is a dead leg in waiting.

The fixes are unglamorous and they work. Flush little-used outlets on a defined schedule and log it. Hold cold below the stored target and hot above the temperatures your assessment specifies, and prove it at sentinel taps [3]. Strip out showers that exist only on paper — a capped, removed branch cannot stagnate. Eyewash and emergency safety showers deserve separate attention because they are rarely run yet built to spray straight at a face; the same low-use logic that governs [Misting systems and humidifiers: Legionella in unexpected places](https://legionella.io/articles/misting-systems-and-humidifiers-legionella-in-unexpected-places/) applies to any fitting that aerosolises water onto people.

## Static water: storage tanks, sprinklers and the cold store

The second risk pool is water that is meant to sit still.

**Cold water storage** sized for a bygone occupancy is the classic warehouse trap. Oversized tanks turn over slowly, lose their thermal margin, and collect debris and sediment. The answer is usually to right-size or compartmentalise storage to match real demand, insulate and lid tanks properly, and inspect them on the schedule your assessment sets.

**Sprinkler and fire-suppression tanks** hold large static volumes by design, and that water is not for drinking. The Legionella question is narrower than people fear: a closed, dedicated fire tank that never aerosolises and never cross-connects to the welfare supply is a low everyday exposure. It matters when it can generate spray — during testing, draining or pump runs — or where a cross-connection lets stagnant tank water reach an outlet people use. Have your competent assessor confirm the separation and the maintenance routine rather than assuming either way. Treat sprinkler tank stagnation as something to characterise on your own system, not a number to guess at.

**Cold stores and chilled DCs** add their own water. Cold store water safety is less about the freezer than about the wet edges around it: washdown hoses and hose-union taps that mist, defrost and condensate management, ante-room welfare, and any humidification used to stop produce drying out. Spray-producing humidification sits in the same category set out for [Legionella in data centres: cooling, humidification and adiabatic systems](https://legionella.io/articles/legionella-in-data-centres-cooling-humidification-and-adiabatic-systems/) — if it makes a mist, it belongs in the assessment.

## One estate, many near-identical sheds

The thing that makes 3PL and logistics FM distinct is repetition. You are rarely managing one building; you are managing fifteen versions of nearly the same building, often acquired or fitted out to a similar spec.

That cuts both ways. A standard shed design means a standard control regime travels well — one written scheme, one multi-site welfare flushing template, one set of sentinel points replicated site to site. But it also means a single design flaw, like a chronically oversized tank or an upstairs welfare core nobody uses, is copied across the whole portfolio. Get the template right and you fix fifteen buildings; get it wrong and you have replicated the same failure fifteen times.

This is where central oversight earns its keep. The coordination challenge of a dispersed estate — consistent records, comparable temperatures, a single view of which site missed its flushing week — is the subject of [Managing Legionella risk across multiple sites](https://legionella.io/articles/managing-legionella-risk-across-multiple-sites/). Remote temperature monitoring suits low-occupancy sites particularly well, precisely because there is rarely anyone on hand to take a manual reading at the far tap. The same logic carries other high-throughput, low-supervision estates such as the terminals and concourses in [Legionella control in airports and transport hubs](https://legionella.io/articles/legionella-control-in-airports-and-transport-hubs/).

## A field checklist for a low-occupancy site

Use this on a building walk and record each line — the value is in the dated evidence, not the tick.

**Welfare outlets**
- Flush every little-used tap, WC and shower on the schedule your assessment sets; log date, outlet and who did it.
- Run hot and cold sentinel temperatures; confirm cold and hot readings meet the assessed targets.
- Identify and remove or cap showers and taps that serve no genuine purpose.
- Operate and record eyewash and emergency safety showers; clean and descale spray heads.

**Stored and static water**
- Inspect cold water storage for temperature, lid, insulation, screens and sediment.
- Confirm storage volume still matches actual occupancy, not the original design.
- Have the assessor confirm sprinkler and fire tanks are separated from the welfare supply, and characterise any aerosol points.

**Cold store and goods handling**
- Assess washdown hoses, hose-union taps and any humidification that produces spray.
- Check defrost and condensate routes are draining, not pooling.

**Across the estate**
- Apply the same written scheme, sentinel points and flushing template to each near-identical site.
- Compare temperatures and missed tasks centrally; flag the outliers.
- Reassess after any occupancy change, mothballing or fit-out.

This is general guidance, not a substitute for a site-specific assessment by a competent person, and nothing here is legal, medical or engineering-design advice. Your own risk assessment, written for each building, sets the temperatures, frequencies and priorities — and the decisions that follow from it are yours to own [5].

## Common questions

### Does a low-occupancy warehouse really need a Legionella risk assessment?
Yes. The duty to assess and control risk applies wherever a water system could foreseeably expose people, and low occupancy increases stagnation rather than removing the duty [1][2].

### Is the fire sprinkler tank a Legionella problem?
Not usually on its own. A dedicated, separated fire tank that never sprays at people and never cross-connects to the welfare supply is a low everyday risk; the concern is aerosol during testing or maintenance, and any cross-connection. Get it confirmed by your assessor rather than assumed [2].

### We have fifteen similar units — can one risk assessment cover them all?
You can build one template and apply it efficiently, but each site needs its own assessment reflecting its actual tanks, outlets and occupancy. Standardise the method, not the conclusions [1][5].

## The next step

Pull your asset list and mark, for one representative site, every outlet that went unused last week and every tank holding more water than today's headcount needs. That single page — unused outlets plus oversized storage — is the warehouse risk in miniature, and it tells you where to point flushing, monitoring and any tank right-sizing before you roll the same fix across the estate.

## Sources

[1] HSE, "Legionnaires' disease - what you must do". https://www.hse.gov.uk/legionnaires/what-you-must-do/index.htm
[2] HSE, "Systems most likely to create legionella risk". https://www.hse.gov.uk/legionnaires/risk-systems.htm
[3] HSE, "Hot and cold water systems". https://www.hse.gov.uk/legionnaires/hot-and-cold.htm
[4] CDC, "How Legionella Spreads". https://www.cdc.gov/legionella/causes/index.html
[5] BSI, "BS 8580-1:2019 - Risk assessments for Legionella control. Code of practice". https://knowledge.bsigroup.com/products/water-quality-risk-assessments-for-legionella-control-code-of-practice-1