When is a Legionella Risk Assessment Needed? Staying Compliant

Legionnaires’ disease, a severe and potentially fatal form of pneumonia, is caused by the Legionella bacteria. These bacteria are naturally present in fresh water environments but can multiply to dangerous levels in man-made water systems, particularly those with stagnant water, suitable temperatures (20-45°C), and a supply of nutrients. For businesses, landlords, and duty holders across the UK, managing the risk of Legionella is not just good practice, it’s a legal obligation.

A fundamental component of this obligation is the Legionella Risk Assessment. But a common question arises: how often is a Legionella Risk Assessment required? The answer isn’t a simple “every X years,” as it depends on several factors and the principle of continuous review.

Zeta uncovers exactly when you must call a Legionella Risk Assessment company to ensure the occupant and visitor safety within your building. 

The Foundation: Your Initial Legionella Risk Assessment

Firstly, it’s a legal requirement under the Health and Safety at Work etc Act 1974 and the Control of Substances Hazardous to Health (COSHH) Regulations 2002 to identify and assess the risks of exposure to Legionella bacteria from work activities and water systems. This means that if you are a duty holder – for example, an employer, landlord, or someone in control of premises – and you have a water system on your property, you must conduct an initial Legionella Risk Assessment.

This initial assessment will:

Identify potential sources of Legionella risk: This includes hot and cold water systems, cooling towers, spa pools, showers, sprinkler systems, and any other water features.

Assess the likelihood of exposure: Considering factors like water temperature, stagnation, presence of scale, sludge, or biofilm.

Determine control measures: Recommending actions to minimise or eliminate the identified risks.

Establish a management plan: Outlining ongoing monitoring, maintenance, and record-keeping requirements.

Zeta provides Legionella Risk Assessments for buildings throughout the UK. Contact us today to get your risk assessment booked in. 

The Key Principle: Regular Review, Not Fixed Intervals

The Health and Safety Executive (HSE) guidance, specifically in their Approved Code of Practice and guidance document L8, “Legionnaires’ disease: The control of Legionella bacteria in water systems” (ACOP L8), does not stipulate a fixed frequency for Legionella Risk Assessments. Instead, it emphasises the principle of regular review.

ACOP L8 states that your risk assessment should be reviewed regularly and immediately if there is any reason to suspect it is no longer valid.

Our Legionella Risk Assessors are equipped to cover and protect any property from the risk of Legionella. Call us today for further information. 

When to Review Your Legionella Risk Assessment

While there isn’t a strict “every two years” or “every five years” rule, there are clear triggers and general guidelines for reviewing your assessment:

Significant Changes to the Water System: This is arguably the most crucial trigger. Any modifications, additions, or significant repairs to your water system, such as installing new pipework, changing water heaters, or adding new outlets, necessitate an immediate review.

Changes in Use of the Building: If the purpose of the building changes, or there’s a significant alteration in occupancy (e.g., from office to residential, or increased tenant turnover), the risk profile may change, requiring a new assessment.

Changes in Personnel: If there’s a change in the people responsible for managing Legionella control, or if new staff are untrained, a review ensures that the new team understands the risks and control measures.

Evidence of System Contamination: If Legionella bacteria are detected in water samples or if there’s an outbreak of Legionnaires’ disease associated with your premises, an immediate and thorough review is essential to identify the source and implement corrective actions.

New Information or Guidance: As scientific understanding evolves or new regulations/guidance are published (like the latest updates to BS 8580-1:2019, which provides guidance on risk assessment), your assessment should be reviewed to incorporate the latest best practices.

After an Incident: Any incident related to your water system that could increase Legionella risk, even if not a confirmed case of disease, should prompt a review.

Recommended Intervals (General Best Practice): While not legally mandated, industry best practice often suggests a full reassessment every two years. For simpler, low-risk systems (e.g., small offices with basic hot and cold water), this might extend to five years, provided there have been no significant changes or incidents. However, relying solely on this timeframe without considering the triggers above is a breach of compliance.

The Importance of Ongoing Monitoring and Management

It’s vital to remember that the risk assessment is just one part of your overall Legionella control strategy. Even between formal reviews, you should be diligently carrying out the ongoing monitoring and maintenance tasks outlined in your initial assessment and management plan. This includes:

• Consistent temperature monitoring of hot and cold water outlets.

• Flushing infrequently used outlets.

• Cleaning and descaling showerheads and spray taps.
• Maintaining accurate records of all checks, tests, and maintenance activities.

Why Zeta Is The Go-To Legionella Risk Assessment Company

Given the complexities, your Legionella risk assessment must be carried out by a competent company. This means people with the necessary knowledge, experience, and training in Legionella control. While you can carry out a basic assessment yourself for very simple systems, for most commercial or multi-occupancy properties, it is highly recommended to engage a specialist, independent Legionella risk assessment company, such as Zeta.

By understanding that Legionella risk assessments are based on the principle of regular review and immediate action upon triggering events, duty holders can ensure continuous compliance, protect public health, and avoid the severe consequences of Legionnaires’ disease. Don’t wait for a fixed date; stay vigilant and review your assessment whenever circumstances dictate. 

Book your Legionella risk assessment today with Zeta.