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    Risk Assessments

What is Legionella?

Legionella is a type of bacterium found naturally in freshwater environments, like lakes and streams. It can become a health concern when it grows and spreads in human-made building water systems such as:

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Showerheads and sink faucets

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Hot water tanks and heaters

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Large plumbing systems

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Cooling towers *

Due to this legionella is a risk for almost all water systems found within buildings and therefore must be adequately and effectively controlled.

* Structures that contain water and a fan as part of centralized air cooling systems for building or industrial processes

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How It Spreads

After Legionella grows and multiplies in a building water system, water containing Legionella then has to spread in droplets small enough for people to breathe in. People can get Legionnaires’ disease or Pontiac fever when they breathe in small droplets of water in the air that contain the bacteria

Less commonly, people can get sick by aspiration of drinking water containing Legionella. This happens when water accidently goes into the lungs while drinking.

In general, people do not spread Legionnaires’ disease and Pontiac fever to other people. However, this may be possible under rare circumstances

The Legionella Risk Assessment

It is important to implement a programme of Legionella risk assessment so as to comply with legal and regulatory obligations. Regular assessments need to be carried out to ensure that Legionella does not exist within a water system, to identify any risks and to act swiftly should it be detected. Our experienced team can carry out a risk assessment and to provide the necessary advise.

Building Managers / Owners Responsibilities

Every business in the UK is required to carry out a legionella risk assessment, regardless of size. Carrying out a risk assessment will find issues or potential issues. We can then help you to get the issues rectified to keep all customers, employees, tenants and others safe.

The risk assessments must be carried out by a competent professional and in accordance with ACOP L8 (4th Edition) & HSG274, CoSHH Regulations & the management of health and safety at work.

It is the responsibility of the building manager / owner to ensure that the Legionella risk assessments are completed on a regular basis. It is required that any potentially sources are identified and managed through prevention and control.

Legionella Bacteria is recognised as preventable, due to this there are stiff penalties for not completing a Legionella Risk assessment on susceptible systems. The potential penalties include fines, prosecution and civil action.


“This leaflet is aimed at employers and people in control of premises, eg landlords, where man-made water systems are used that could be a potential source for legionella bacteria growth. It will help you to understand the health risks associated with legionella. Legionnaires’ disease: The control of legionella bacteria in water systems provides further details about how to manage and control the risks in your system.”

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Systems that
require LRA

As legionella naturally exists in water that means that all water systems should have an adequate Legionella Risk Assessment carried out on them, with special attention to be paid to systems that are more at risk of harbouring and spreading Legionella Bacteria.

Legionella risk assessments should be carried out on systems that:

Have a water temperature of between 20-45°C

Store water, or re-circulate water in the system

Have contamination from rust, iron oxide sludge, organic matter or biofilms

Release water droplets, such as showers or cooling tower aerosols

Are used by people who are more susceptible to developing Legionnaires’ Disease (Young, Old & Immuno-compromised)

Hot and cold water systems

Spa pools, swimming pools and hot tubs

Humidifiers, misters and wet scrubbers

Water Features

Our Legionella Risk Assessment

Our Legionella Risk Assessment (LRA) will include:

The management Structure of the organisation with regards to legionella.

Asset Register


Schematic Diagram

Prioritized list of identified hazards and the associated risks.

A guidance section to give practical measures which can be undertaken to reduce / remove the highlighted areas within the risk assessment

Reminder when another Risk assessment is due (we recommend every two years)