Schematic Diagram

How to Get Legionella Compliant?

Below is simplified action plan to become legionella complaint. Following these steps will help prevent and control legionella risks.

Legionella Risk Assessment

Identify the legionella risks present within the water systems.

Water Testing & Analysis

Water testing and & analysis should be undertaken to determine how affective the legionella control measures are.


Implement a schematic drawing of the water systems.

Water Logbook

Implement a water logbook for ongoing monitoring tasks and record keeping.

Remedial Action

Remove or reduce the risks identified within the risk assessment.


Ensure that all responsible persons that form part of the water safety group on this page are suitably trained and competent.

Managing the Risk

Common factors that contribute to Legionella outbreaks include the following.


Inadequate management, lack of training and poor communication have been identified as contributory factors in outbreaks


People involved in assessing risk and applying precautions are competent, trained, and aware of their responsibilities.


The use of contractors does not absolve the Duty Holder of responsibilities for ensuring correct control measures.

Organisations should make reasonable enquiries to satisfy themselves of the competence of contractors. Illustrations of levels of service to be expected from service providers can be found in the Code of Conduct developed by LCA (Legionella Control Association) for those members.

Controlling the Risk

Legionella can thrive anywhere as long as the conditions are right. The HSE has given the following 6 guidelines to prevent the spread of Legionnaires’ Disease:


Outlets such as: showers, taps, hoses, toilets. All of these can spray droplets of water. All of the stated systems can produce the environment for Legionella bacteria to multiply.


Legionella thrives at 37 degrees, which is body temperature. However, Legionella dies at 60 degrees; therefore we need to ensure we heat the water in our boilers/water heaters to at least 60 degrees. It is common for people to turn boilers and water heaters down to save on energy bills, but this won’t kill Legionella, instead it will leave it dormant.

Water Treatment

In systems where we cannot use temperature as a means of control, we can use chemical treatments. You should always use a competent person to treat your appliances to ensure legionella is dealt with correctly. Prime examples are hot tubs, swimming pools and cooling towers.


Water should not stagnate anywhere within the system. By keeping pipe lengths as short as possible, and removing any redundant pipe work is key. Flushing regimes are put in place to ensure water flow is kept moving throughout the entire system. This standard has gone through a consultation period that ended on the 23rd August, 2013.


Poor water system conditions promote legionella growth. Conditions might include limescale, sediment, rust, sludge, algae, and sunlight.


Materials that encourage growth such as steel, rubber, lead pipework. Legionella needs nutrients and this can come in the form of the materials in your water system. You will need to make sure any materials used are not corrosive, so that Legionella growth is limited. Any installer you use for plumbing or water treatment purposes should be a competent person and they should source all of their material through the Water Fitting and Materials Directory (WRAS directory).