How Often Should A Legionella Risk Assessment Be Reviewed

“

How Often Should a Legionella Risk Assessment Be Reviewed?

Legionella risk assessments are a key part of UK property compliance, especially for buildings with water systems where Legionella bacteria could multiply. For landlords, managing agents, and property professionals, the question isn’t just whether an assessment is completed—it’s how often the risk assessment needs to be reviewed to remain valid and legally defensible.

In this guide, we explain the typical review frequency, what triggers an “out-of-date” assessment, and how Propcert can help you keep your water safety documentation in order.

Why Legionella Risk Assessments Need Regular Review

A Legionella risk assessment is not a one-time exercise. The risk to occupants can change over time due to:

• changes in water system design or use
• maintenance practices (or lack of them)
• temperature fluctuations and system downtime
• changes in occupancy patterns
• equipment changes such as pumps, tanks, boilers, or calorifiers
• the discovery of defects, leaks, scale build-up, or other issues

That’s why the assessment must be reviewed and, where necessary, updated to reflect current conditions. A review helps ensure control measures remain effective and demonstrates due diligence in the event of an incident or inspection.

How Often Should a Legionella Risk Assessment Be Reviewed in the UK?

There isn’t a single “fixed” review interval that applies to every property, because Legionella risk depends on the building and its water systems. However, a commonly accepted approach in the UK is:

Review every 12 months (at least) for higher-risk premises.

For some properties, a shorter or longer interval may be appropriate, but annual review is widely used as a practical benchmark—particularly where systems are complex, heavily used, or require frequent monitoring.

In lower-risk cases, a less frequent review may be possible, but only if the risk assessment outcome and property circumstances justify it. Even then, it should still be reviewed sooner if conditions change.

The Legal Expectation: Review When Things Change

The Health and Safety Executive (HSE) expectations are clear: you must review your Legionella risk assessment regularly and also after any significant changes to the premises or systems.

A review should be triggered if:

• there are changes to water systems, pipework, storage, or outlets
• the building layout or use changes (e.g., conversion to flats, new tenant type)
• system downtime occurs (e.g., long vacancies, shut-downs, mothballing)
• maintenance is altered or contractors change
• temperature or flow patterns change
• water samples indicate elevated contamination or results outside expected norms
• any suspected Legionella case occurs
• defects, corrosion, scale, biofilm, leaks, or poor housekeeping are identified

In short: annual review is a common minimum expectation, but the assessment must be updated whenever conditions make it no longer accurate.

What Happens if You Don’t Review Regularly?

If a Legionella risk assessment is allowed to become outdated, it can create compliance risk for dutyholders. Potential consequences include:

• non-compliance with health and safety expectations
• control measures not reflecting the current risk level
• missed opportunities to identify defects (e.g., scaling, poor circulation)
• greater likelihood of health incidents if water systems aren’t managed properly
• reduced defensibility in investigations or audits

Even when the assessment is technically “in date” on paper, failing to review it following changes can still be problematic.

Legionella Risk Assessment Review Frequency by Property Type (Practical Guidance)

While every building is different, the following practical guidance is commonly applied when deciding review frequency:

• Higher-risk settings (e.g., larger developments, complex hot and cold systems, healthcare-like environments, care facilities, or sites with higher occupancy variability): typically at least annually.
• Medium-risk settings: often reviewed annually, or sooner if there are system changes or operational disruptions.
• Lower-risk settings: may be reviewed less frequently, but only if the risk assessment clearly supports it and there are no significant changes.

If you’re unsure which category your property falls into, it’s best to treat it conservatively and schedule an appropriate review interval.

Do Landlords Need Legionella Assessments?

In the UK, the duty to manage risks applies to those responsible for premises and water systems. For landlords, that often means ensuring safe water management and obtaining the necessary documentation where required.

Even where a full Legionella assessment may not always be expected for every small property scenario, landlords and agents still need to take reasonable steps to understand and control risk—particularly for systems such as communal hot water in blocks of flats or buildings with centralised equipment.

Because requirements can vary depending on the property and system type, the safest approach is to get clear guidance for your specific setup and ensure your assessment is reviewed appropriately.

How to Know When Your Legionella Risk Assessment Needs Updating

Beyond the date on the document, look for these “update signals”:

• New or changed water outlets (e.g., additional showers, new taps, changed usage)
• Hot water system refurbishment, boiler replacement, calorifier changes, or pump upgrades
• Frequent callouts for leaks, pressure issues, or poor performance
• Evidence of biofilm, scale, sludge, or corrosion
• Water temperatures not staying within expected control ranges
• Prolonged non-occupancy or intermittent use patterns
• Any changes in maintenance regime, sampling strategy, or monitoring records

If any of the above apply, a review should not wait until the next scheduled date.

What a Legionella Review Should Include

A proper review generally involves:

• confirming the premises and water systems still match the original assessment
• checking control measures are in place and operating effectively
• reviewing maintenance logs and temperature monitoring records
• considering any incidents, defects, or changes since the last review
• reassessing risks and updating actions where needed

Where required, actions may include adjustments to temperatures, flushing routines, cleaning, disinfection, improved monitoring, or sampling.

Keep Your Compliance Streamlined with Propcert

Managing multiple compliance duties across a portfolio can be time-consuming—especially when you need documents renewed, updated, and produced quickly for tenants, buyers, or agents.

At Propcert, we help property professionals stay compliant with a straightforward, nationwide service and fast turnaround. We specialise in property certification and safety documentation, supporting landlords, estate agents, and property teams with essential checks such as:

• EPCs (Energy Performance Certificates)
• EICRs (Electrical Installation Condition Reports)
• Gas safety certificates

If you’d like help organising your compliance schedule—including understanding renewal timelines and ensuring you have the right paperwork ready—contact Propcert for a quick, hassle-free booking.

Frequently Asked Questions

How often should Legionella risk assessments be reviewed?

A common benchmark is at least annually for higher-risk or complex premises. However, the assessment must also be reviewed after any significant change to the building or water systems.

Does every building need the same review frequency?

No. Review intervals depend on the building’s risk level, water system complexity, and how the premises are used. Some lower-risk settings may justify longer intervals, but any major change should trigger an earlier review.

What triggers a review before the next annual date?

Examples include system alterations, prolonged downtime, changes to occupancy patterns, evidence of scaling/biofilm, temperature control issues, or any suspected incident.

Who should manage Legionella compliance?

The dutyholder (such as a landlord, managing agent, or property operator responsible for the premises) is typically expected to manage and control risk, including maintaining review and documentation.

How can Propcert help?

Propcert supports UK landlords and property professionals with fast, straightforward booking for essential certification such as EPCs, EICRs, and gas safety certificates, helping you keep compliance organised across properties.

Need help planning your compliance renewals? Get in touch with Propcert.co.uk to arrange your next property certification quickly.

“