The control of legionella bacteria in hot and cold water systems
This guidance is for dutyholders, which includes employers, those in control of premises and those with health and safety responsibilities for others, to help themcomply with their legal duties.
These include identifying and assessing sources of risk, preparing a scheme to prevent or control risk, implementing, managing and monitoring precautions, keeping records of precautions and appointing
a manager responsible for others.
The guidance gives practical advice on the legal requirements of the Health and Safety at Work etc Act 1974, the Control of Substances Hazardous to Health Regulations 2002 concerning the risk from exposure to Legionella and guidance on compliance with the relevant parts of the Management of Health and Safety at Work Regulations 1999.
How do I control the risks from legionella in my water system?
The key point is to design, maintain and operate your water services under conditions that will either prevent or adequately control the risk from legionella bacteria. It is important that you either have, or have access to, competent help to fulfil these obligations.
If you identify a risk that you are unable to prevent, you must introduce appropriate controls. You should introduce a course of action that will help you to control any risks from legionella by describing:
- your system and its component parts eg developing a schematic diagram
- 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 to ensure risks are being managed and how often
You should where appropriate:
- 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 by removing redundant pipe work
- avoid materials that encourage the growth of legionella (The Water Fittings & Materials Directory references fittings, materials, and appliances approved for use on the UK Water Supply System 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
Is it necessary to clean and disinfect my water system?
It is important to maintain the cleanliness of your water system. The mechanisms and frequency for doing this will depend on the system you have and whether cleaning or disinfecting is being done routinely or because of a problem identified during monitoring. The frequency and method of routine cleaning and disinfecting should be identified within your risk assessment. This will take account of factors such as whether the system is open or closed, the type and level of contamination, and the population that could be exposed.
Under general health and safety law, as a landlord you have health and safety duties and need to take suitable precautions to prevent or control the risk of exposure to legionella.
Letting agents and landlords are obliged by law to carry out risk assessments for legionnaire’s disease, and if necessary, take action. You should have a Legionella Risk Assessment every 2 years if you rent out a property.
Having a risk assessment is your responsibility and will help you to establish any potential risks and implement measures to either eliminate or control risks.
After a risk assessment has been carried out you will receive a certificate which will be valid for 2 years.