Step 1: Identify the Hazards
The first step of a legionella risk assessment is to identify any potential sources of risk within the property. Create a list of the water systems in the property and make a note of how each of them could be a legionella hazard. The HSE states that legionella risk assessment needs to identify whether:
- Water is stored or re-circulated as part of your system.
- The water temperature in some or all parts of the system is between 20–45 °C.
- There are sources of nutrients such as rust, sludge, scale and organic matters.
- Conditions are present to encourage bacteria to multiply.
- It is possible for water droplets to be produced and, if so, whether they could be dispersed over a wide area.
Sources of risk can be identified by sight or by consulting the property’s schematic diagram, which shows the layout of all water systems within the property.
Step 2: Consider Who May be At Risk
This step involves making a record of who is most likely to be affected by any potential legionella bacteria in the property. This stage is essential to prove that landlords have considered who may be at risk.
Make a note of everyone who may be present in the property, including employees, contractors, residents and visitors, and then consider whether anyone may be more at risk than others, such as people in later life, children, those who smoke, those with existing illnesses or those with weak immune systems.
Step 3: Implement Control Measures
Before implementing new legionella controls take a look at any controls that are already in place in the property and consider whether these are sufficient or need updating. Suitable control measures include:
- Implementing regular inspection and maintenance procedures.
- Monitoring water temperatures.
- Regularly cleaning parts of the water system, such as showerheads and baths.
- Preventing access to water tanks and pipework by unauthorised people.
- Flushing out water systems prior to letting a property to remove stagnant water.
- Removing any redundant pipework.
- Setting control parameters, such as ensuring hot water is stored above 60°C.
Monitoring bacteria levels and water testing should only be carried out by a specialist service, such as a water treatment company or consultant, and are generally not required by domestic properties due to their low level of risk. Landlords should not try to test the water or monitor bacteria levels unless they are properly supervised.
Once controls are implemented, remember to advise tenants of anything that they need to maintain. For example, regularly cleaning shower heads, not adjusting the temperature of the hot water heater and informing the landlord of any problems that they discover.
Step 4: Keep Records
The findings of the risk assessment should be written down or typed up into a document to act as proof that landlords are complying with their responsibilities.
A record should be kept of all identified hazards and their control measures, plus details of who the duty holder is and a description of the water system present. These records should be retained at least two years. Landlords should also retain records of any monitoring, inspections, tests or checks carried out, and their dates, for at least five years.
Step 5: Review the Risk Assessment
Landlords should check on a regular basis to see whether there have been any changes in the property that may affect the risk assessment. It’s recommended that risk assessments are reviewed every two years, plus each time changes are made or new information comes to light. For example when:
- There are changes to the water system or its use.
- There are changes to the use of the building in which the water system is installed.
- New information about risks or control measures becomes available.
- The results of checks indicate that control measures are no longer effective.
- A case of legionellosis associated with the system has been diagnosed.
For more information, please use the link to HSE – https://www.hse.gov.uk/pubns/indg458.htm