Why Is a Legionella Risk Assessment Important?

Legionella bacteria occur naturally in lakes, rivers and reservoirs. Problems arise when the bacteria enter artificial water systems and find suitable conditions to multiply.

Warm water, poor circulation, stagnant pipework, scale and biofilm all encourage bacterial growth. If contaminated water becomes airborne through showers, spray taps or similar outlets, people can inhale tiny droplets containing the bacteria. In some cases, this can lead to Legionnaires’ disease, which is a serious form of pneumonia.

Most domestic rental properties have relatively simple water systems and are considered low risk. However, low risk does not mean no risk. A suitable assessment helps identify any issues before they become a problem.

Do Landlords Have a Legal Responsibility?

Yes. Landlords have a duty to consider the risk of Legionella bacteria within their rental properties.

Under Section 3(2) of the Health and Safety at Work etc. Act 1974, landlords must take reasonable steps to protect tenants and other people who may be affected by their property. Guidance published by the Health and Safety Executive also explains that landlords should assess the risk and introduce suitable control measures where necessary.

In many domestic properties, these control measures are simple. For example, maintaining suitable hot water temperatures, ensuring little-used outlets are flushed regularly and keeping the water system clean can significantly reduce the risk.

What Happens During the Assessment?

Our assessment always begins with a detailed inspection of the property’s water system.

We take time to understand how the building is supplied with water before examining the accessible components. Depending on the property, the inspection may include hot water cylinders, cold water storage tanks, expansion vessels, pipework, showers, taps, flexible hoses and any other relevant equipment.

During the visit we also check water temperatures at representative outlets. Temperature control is one of the most effective methods of reducing Legionella growth, so accurate readings form an important part of the assessment.

Where accessible, we inspect pipe insulation, identify dead legs or redundant pipework and look for evidence of scale, corrosion or poor maintenance. We also consider whether water may remain stagnant because of low occupancy or infrequent use.

What Do We Look For?

Every property is different, but our assessor typically looks for:

• Hot water temperatures reaching recommended levels.
• Cold water temperatures remaining below recommended limits.
• Dead legs and redundant pipework.
• Little-used taps or showers.
• Poorly insulated pipework.
• Water storage tanks and their condition.
• Signs of corrosion, scale or biofilm.
• General cleanliness of the water system.
• Any features that could encourage bacterial growth.

Rather than simply recording defects, we explain why each observation matters and whether it presents a significant risk.

What Happens After the Inspection?

Following the site visit, we prepare a comprehensive Legionella risk assessment report.

The report explains the water system, identifies any hazards and provides practical recommendations where improvements are required. We avoid unnecessary technical language wherever possible so landlords and property managers can understand the findings easily.

If no significant issues are identified, the report confirms that the existing control measures appear suitable at the time of inspection. Where improvements are recommended, we prioritise them according to the level of risk.