Lesson 1: Legionella Risk Management

Lesson Overview

Legionella is a type of bacteria that can develop in water systems and, under certain conditions, cause a serious form of pneumonia known as Legionnaires’ disease. Although the risk in most domestic rental properties is generally low, landlords in Scotland have a legal duty to assess and manage the risk to ensure the health and safety of their tenants.

Managing Legionella does not usually require complex testing or expensive specialist inspections. Instead, landlords are expected to carry out a simple risk assessment, identify any potential hazards, take reasonable precautions to minimise risk, and keep appropriate records.

This lesson explains what landlords must do to comply with their legal obligations, how to identify low-risk and high-risk properties, the importance of water system flushing and routine checks, and the documentation needed to demonstrate compliance.

By the end of this lesson, you will understand:

• Your responsibilities for managing Legionella risks.
• The difference between low-risk and high-risk properties.
• How to carry out basic water system maintenance.
• What records should be kept to demonstrate compliance?

Learning Objectives

After completing this lesson, you will be able to:

• Explain the risks associated with Legionella bacteria.
• Carry out a basic Legionella risk assessment.
• Identify higher-risk properties and water systems.
• Implement simple preventative measures.
• Maintain suitable records of risk management activities.

What is Legionella?

Legionella is a naturally occurring bacteria that can grow in water systems under certain conditions.

People become infected by inhaling tiny water droplets (aerosols) that contain the bacteria. It is not spread by drinking contaminated water.

If inhaled, Legionella can cause:

• Legionnaires’ disease (a serious type of pneumonia).
• Pontiac fever (a milder flu-like illness).

Although relatively uncommon, Legionnaires’ disease can be life-threatening, particularly for older adults, smokers, and people with weakened immune systems.

How Legionella Develops

Legionella bacteria are more likely to multiply when:

• Water temperatures remain between 20°C and 45°C.
• Water is stored for long periods without movement.
• Pipework contains stagnant water.
• Scale, sludge, or rust builds up in the system.
• Water systems are poorly maintained.

Keeping water moving and maintaining appropriate temperatures significantly reduces the risk.

Legal Responsibilities for Landlords

Under health and safety law, landlords have a duty to assess and control the risk of exposure to Legionella in rental properties.

This means landlords should:

• Assess the risk of Legionella.
• Take reasonable steps to reduce identified risks.
• Maintain water systems in good condition.
• Provide safe water systems for tenants.
• Keep appropriate records where necessary.

There is no legal requirement for landlords to commission professional Legionella testing in every property. The level of action required depends on the level of risk.

Conducting a Basic Legionella Risk Assessment

A basic risk assessment should consider:

• The type of water system.
• The age and condition of the plumbing.
• Whether water is regularly used.
• Whether there are any unused outlets.
• Whether water is stored in tanks.
• The likelihood of water remaining stagnant.

For many standard domestic properties, a simple documented assessment is sufficient.

Low-Risk Properties

Most privately rented homes fall into the low-risk category.

Examples include:

• Modern houses or flats.
• Properties with combi boilers.
• Homes where water is used regularly.
• Properties without stored water tanks.
• Well-maintained plumbing systems.

For these properties, routine maintenance and sensible precautions are usually adequate.

High-Risk Properties

Some properties require closer attention due to increased risk.

Examples include:

• Older buildings with ageing plumbing.
• Properties with cold water storage tanks.
• Homes left vacant for extended periods.
• Large properties with complex plumbing systems.
• HMOs with multiple bathrooms.
• Properties with infrequently used outlets.

Additional monitoring and maintenance may be appropriate in these cases.

Water System Flushing

Flushing water systems helps prevent stagnant water, which reduces the likelihood of Legionella growth.

Flushing should involve:

• Running all taps.
• Running showers.
• Flushing toilets.
• Operating outside taps where fitted.

Water should be allowed to flow long enough to replace stagnant water with fresh water.

When Flushing is Recommended

Flushing is particularly important:

• Before new tenants move in.
• After a property has been vacant.
• Following extended periods of non-use.
• After plumbing alterations.
• Where outlets are rarely used.

Regular use of all outlets is one of the simplest ways to reduce risk.

Routine Water System Checks

Landlords should periodically inspect water systems for:

• Leaking pipework.
• Corrosion.
• Damaged insulation.
• Signs of stagnant water.
• Scale or debris.
• Poorly functioning taps or showers.

Any defects should be addressed promptly.

Temperature Management

Maintaining appropriate water temperatures helps reduce bacterial growth.

As a general guide:

• Cold water should remain as cold as practicable.
• Hot water should be stored and distributed at temperatures that discourage bacterial growth while remaining safe to avoid scalding risks.

Landlords should ensure heating systems and hot water cylinders are functioning correctly and are serviced in accordance with the manufacturer’s recommendations.

Shower Heads and Hoses

Shower heads can accumulate scale and biofilm, creating conditions where bacteria may develop.

Good practice includes:

• Cleaning shower heads regularly.
• Descaling where necessary.
• Replacing damaged hoses.
• Inspecting for blockages.

This is particularly important after long periods of vacancy.

Empty Properties

Vacant properties require additional attention because water may remain stagnant.

Before reoccupation:

• Flush the entire water system.
• Run all taps and showers.
• Check hot water systems.
• Inspect tanks if present.
• Ensure the property is ready for safe occupation.

Documentation Requirements

Keeping records demonstrates that landlords have considered and managed the risk appropriately.

Useful records include:

• Legionella risk assessments.
• Inspection dates.
• Flushing records.
• Maintenance logs.
• Plumbing repair records.
• Water system upgrades.
• Contractor reports (where applicable).

The amount of documentation should be proportionate to the level of risk.

Tenant Information

Although landlords remain responsible for risk management, tenants can also help reduce risk.

Tenants should be encouraged to:

• Use all taps and showers regularly.
• Report plumbing defects promptly.
• Notify the landlord if the property will be vacant for a prolonged period.
• Report unusual water quality issues.

Providing simple written guidance at the start of the tenancy is considered good practice.

Common Compliance Mistakes

Common landlord errors include:

• Assuming Legionella is only a commercial property issue.
• Ignoring long-term vacant properties.
• Forgetting to flush systems before new tenants move in.
• Not documenting basic risk assessments.
• Failing to inspect stored water tanks.
• Ignoring plumbing defects that may encourage water stagnation.

Best Practice Approach

Professional landlords should:

• Carry out a basic Legionella risk assessment for every property.
• Review assessments periodically and after significant plumbing changes.
• Flush water systems before each new tenancy and after periods of vacancy.
• Encourage tenants to report plumbing issues quickly.
• Maintain plumbing systems in good condition.
• Keep proportionate records of inspections and maintenance.
• Include Legionella checks within routine property inspection programmes.

Case Study

A landlord owns a two-bedroom flat that has been empty for four months between tenancies. Before the new tenant moves in, the landlord runs all taps, showers and toilets, checks the hot water system, and records the flushing date in the property’s maintenance log.

During the inspection, a shower head is found to be heavily scaled. It is cleaned and replaced before the tenancy begins.

The property is handed over with a safe and fully operational water system.

Lesson: Simple preventative measures, carried out before occupation, can significantly reduce the already low risk of Legionella in domestic rental properties.

Key Takeaways

• Landlords have a legal duty to assess and manage the risk of Legionella.
• Most domestic rental properties are considered low risk, but every property should be assessed.
• Stagnant water is the primary factor that increases the risk of Legionella growth.
• Flushing water systems after periods of vacancy is an effective preventative measure.
• Regular inspection and maintenance of plumbing systems help minimise risk.
• Keeping appropriate records demonstrates compliance and good property management.
• A proportionate, risk-based approach is expected rather than unnecessary testing.

Lesson Summary

Legionella risk management is an important part of maintaining a safe and healthy rental property. While the risk in most homes is low, landlords must take reasonable steps to assess, control, and monitor water systems. By carrying out simple risk assessments, flushing water systems when needed, maintaining plumbing, and keeping clear records, landlords can fulfil their legal responsibilities and provide a safe environment for their tenants.

In the next lesson, you will learn about Energy Performance Certificates (EPCs), Ventilation, and Damp & Mould Prevention, exploring how energy efficiency and good ventilation contribute to healthier, compliant rental properties.