top of page


Legionella System Of Control or Written Scheme


In some cases a formal system of control may have to be implemented. This is usually determined after a risk assessment is completed. This is a written record of your buildings health with respect to water systems. We can help create your written policies and a schedule of testing that will comply with relevant guidance from the HSE.  

Records should include details of the:

  • person or persons responsible for conducting the risk assessment, managing, and implementing the written scheme

  • significant findings of the risk assessment

  • written control scheme and details of its implementation

  • details of the state of operation of the system, i.e. in use/not in use

  • results of any monitoring inspection, test or check carried out, and the dates.


These records should be retained throughout the period for which they remain current and for at least two years after that period. Records kept in accordance with should be retained for at least five years.

Preventing or Controlling the Risk

You should consider whether you can prevent the risk of legionella by looking at the type of water system you need. The key point is to design, maintain and operate your water services under conditions that prevent or adequately control the growth and multiplication of legionella.

If you identify a risk that you are unable to prevent, you must introduce a course of action ie a written control scheme, that will help you to manage the risk from legionella by implementing effective control measures, by describing:

  • your system (schematic drawing)

  • who is responsible for carrying out the assessment and managing its implementation

  • the safe and correct operation of your system

  • what control methods and other precautions you will be using

  • what checks will be carried out, and how often will they be carried out, to ensure the controls remain effective


You should:

  • ensure that the release of water spray is properly controlled

  • avoid water temperatures and conditions that favour the growth of legionella and other micro-organisms

  • ensure water cannot stagnate anywhere in the system by keeping pipe lengths as short as possible or removing redundant pipework

  • avoid materials that encourage the growth of legionella , as approved by the Water Regulations Advisory Scheme

  • keep the system and the water in it clean

  • treat water to either control the growth of legionella (and other microorganisms) or limit their ability to grow

  • monitor any control measures put in place

  • keep records of these and other actions taken, such as maintenance or repair work



Managing The Risk 


As an employer, or person in control of premises, you must appoint someone competent to help you meet your health and safety duties and to take responsibility for controlling any identified risk from exposure to legionella bacteria. A competent person, often known as the responsible person, is someone with sufficient authority, competence, necessary skills, knowledge of the system, and experience. The appointed responsible person could be one, or a combination of:

  • yourself

  • one or more workers

  • someone from outside your business


If there are several people responsible for managing risks, e.g. because of shift-work patterns, you must make sure that everyone knows what they are responsible for and how they fit into the overall risk management of the system.

Legionella Control- Action

In some cases you will already have a risk assessment in place, and may have actions identified pertaining to monitoring. Depending on the design of your building this could be an easy task or could be a considerable drain of your resource. Our monitoring service is designed to remove this burden where we would schedule relevant tasks and execute on your behalf.



bottom of page