Managing Legionella Risk: A Guide for Property Managers

Legionella is a type of bacteria found in water systems. If inhaled through small water droplets, it can cause Legionnaires’ disease - a serious lung infection that can be fatal, especially for older or vulnerable people.

For property managers, managing the risk of Legionella is both a legal duty and a key part of keeping residents safe. Whether managing one building or several, you must take steps to prevent bacteria from growing in water systems and ensure your property is compliant with safety regulations.


What is Legionella and Where is it Found?

Legionella bacteria grow in water, especially when it’s warm (between 20°C and 45°C) and stagnant. The risk increases when water systems are not properly used, cleaned, or maintained.

Common sources of Legionella include:

  • Water storage tanks

  • Hot and cold water systems

  • Showers and taps that are not used regularly

  • Pipework with dead legs (sections with no flow)

  • Air conditioning systems with water cooling systems

  • Cooling towers

The danger comes from inhaling tiny droplets of water from these systems, often through mist or spray. 

Legal Duties and Guidance

The main law covering Legionella risk is the Health and Safety at Work Act 1974, supported by the Control of Substances Hazardous to Health (COSHH) Regulations and Approved Code of Practice (ACoP) L8, published by the Health and Safety Executive (HSE).

  • Health and Safety at Work Act 1974:  The primary legislation which places a general duty on employers and those in control of a premises to ensure health and safety.

  • Control of Substances Hazardous to Health Regulations (COSHH): These regulations provide a framework for controlling the risks from biological agents including Legionella.

  • Approved Code of Practice (ACOP) L8: Developed by the Health and Safety Executive, this provides detailed guidance on controlling Legionella in water systems.

Under these laws, property managers and landlords have a duty to assess the risk of Legionella in their buildings, control and reduce those risks where possible, and keep records of any checks and maintenance carried out. In most residential settings, this means ensuring that water systems are safe and regularly checked - even if the risk is low.

Who is Responsible?

A “duty holder” for the building must be named - this could be the building owner, managing agent, or other responsible person. The duty holder must meet the following responsibilities:

  • Risk Assessments:

Duty holders must conduct a risk assessment to identify and assess the risk of Legionella contamination in their water systems.

  • Control Measures: 

Based on the risk assessment, duty holders must implement appropriate control measures to prevent or minimise the risk of Legionella exposure.

  • Management and Monitoring:

Duty holders must establish and implement a water management program, including regular inspections, maintenance, and monitoring of the water systems.

  • Record Keeping:

Duty holders must keep records of their risk assessments, control measures, inspections, and any incidents related to Legionella.

Landlords have a specific legal duty to ensure that rented properties are safe and free from health hazards under the Health and Safety at Work Act. This includes Legionella control. 

If in any doubt, best practice for property managers is to begin with a fresh risk assessment. You should stay informed about any developments in the requirements of the law (as well as continuously training any other staff). You must also keep clear, accessible records of any flushing, temperature checks, or tank inspections etc.

Legionella Risk Assessments & Ongoing Control

During a risk assessment, a qualified person inspects the building’s water systems to look for:

  • Stagnant or infrequently used outlets

  • Water temperatures that could support bacterial growth

  • Design issues (e.g. long or unused pipe runs)

  • Cleaning and maintenance records

We advise that risk assessments be repeated every 2 years as a minimum. If there are any changes made to the building, if there are any changes to the management, the water system is modified, a Legionella case is confirmed or the system is left unused for a long period for any reason, a fresh risk assessment should be carried out immediately. Managing Legionella risk is about routine, records, and readiness. Between risk assessments, there are some simple tasks you can carry out to minimise and keep ongoing control of your risks:

  • Flush infrequently used outlets (e.g. vacant flats, communal spaces, garden taps etc.)

  • Check water temperatures (keep temperatures either below 20°C or above 50°C)

  • Dismantling and cleaning shower heads, hoses and taps regularly

  • Inspect tanks and system parts for biofilm or scale

  • Keep records of checks, maintenance, and training

In Conclusion

Managing Legionella risk doesn’t need to be complicated, but it must be consistent and well-documented. Even in low-risk residential settings, regular checks and proper records are essential.

By understanding your duties, scheduling risk assessments, and taking simple steps to control bacteria growth, you can protect your residents and stay compliant with the law.

If you require any assistance or guidance around your Legionella assessments or compliance, feel free to give us a call for a zero-pressure chat. We’d be more than happy to help.

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