The Control of Substances Hazardous to Health (COSHH) Regulations state that there is a statutory duty to manage and control the risk of legionella in water systems. Legionella bacteria is commonly found in water between 20 and 45°C and can cause legionnaires disease which is a potentially fatal type of pneumonia contracted by inhaling bacteria in airborne water droplets.

In order to ensure a safe environment for employees and customers, water safety regulations must be adhered to. Here we outline some of the top responsibilities pertaining to water systems in your business.


The primary method used to control the risk of legionella in water systems is temperature control. Hot water should be stored at 60°C or higher and should be distributed at 50°C or higher. For cold water it should be stored and distributed at 20°C or lower. This is due to the temperatures that the legionella bacteria lay dormant.

The water systems must be routinely checked by qualified personnel to ensure the control of legionella and compliance of the system within regulations and laws. Remaining compliant may seem like a daunting task, but with the help of a compliance maintenance team your business’ needs can be managed effectively.

Authority Responsibility

The authorities have a responsibility to inform the public of the risks of legionella bacteria in water systems and to comply with this responsibility by sharing legislation and regulations on legionella control. There are Approved Codes of Practice (L8 ACoP 2001) which dictate the regulations for the control of legionella in water systems. The COSHH regulations also provide a framework of actions to control the risk from a range of hazardous substances, including legionella.


The owner or operator of a publicly accessible water system is referred to as the ‘duty holder’; this includes the employer in situations in which employees work in a facility where water is stored. The duty holder must comply with the relevant legislations and appoint a ‘responsible person’ who is to take day-to-day responsibility for controlling the risk of legionella. Duty holders must carry out risk assessments of employees in the workplace contracting legionnaires disease.

Responsible Person

A designated person who is responsible for legionella control should be selected within the business.  The appointed responsible person should have the knowledge to perform the tasks necessary and be able to carry out operational procedures in a timely and effective manner.

How can employing a compliance maintenance team help?

Compliance maintenance teams are available to help legionella control in water systems. They are able to assist with risk assessments, water treatment and bacteria control, tank refurbishment or replacement, and provide training to the person responsible for legionella control in the business.

At MSL, we are available to make sure your business is compliant with water system regulations among other legislation. To discuss our compliance maintenance program, contact us on 0333 1234450.