How Often Do Landlords Need a Legionella Risk Assessment? The 2026 Answer (and What Happens If You Skip It)

If you are searching for a legionella assessment for landlords, here is the short answer: there is no fixed statutory renewal interval in the UK.

A Legionella risk assessment must remain suitable and sufficient for the property. As practical good practice, most standard rental properties are reviewed around every two years. Higher-risk properties, including HMOs, homes with cold-water storage tanks, complex systems or long void periods, should generally be reviewed annually or more frequently where necessary.

You must also review the assessment whenever the occupancy, tenant circumstances or water system changes. Waiting for a convenient date in the diary is not a compliance strategy. Water systems, rather unhelpfully, do not check your calendar.

What is the legal position for landlords in 2026?

Landlords have a duty of care to protect tenants from health and safety risks in rented accommodation. This includes managing the risk of exposure to Legionella bacteria.

The Health and Safety at Work etc. Act and the Control of Substances Hazardous to Health Regulations provide the broader legal framework. The HSE’s Approved Code of Practice, commonly known as L8, explains how risks from Legionella should be assessed and controlled.

L8 does not state that every landlord must renew an assessment every 12 or 24 months. It requires the assessment to be reviewed regularly and whenever there is reason to believe it is no longer valid.

For a typical low-risk property with a mains-fed cold-water supply, an instantaneous combi boiler and regular water use, a two-year review is widely used as a sensible benchmark. It is not an automatic expiry date.

The important point is simple: you need to demonstrate that the risk has been considered, controlled and reviewed when circumstances change.

How often do you need a Legionella risk assessment?

For most standard rental properties, review the assessment:

• Before the property is first let
• Approximately every two years as a practical baseline
• When a new tenant or household moves in
• After a long period of vacancy
• Following changes to the plumbing or heating system
• When monitoring or maintenance identifies a concern
• Immediately after any incident or suspected exposure

For higher-risk properties, consider an annual Legionella risk assessment review. This may be appropriate for HMOs, buildings with stored water, properties with tanks or cylinders, communal systems, complex pipework, vulnerable occupants or repeated void periods.

The correct frequency depends on the actual risk. A modern one-bedroom flat with a combi boiler is not managed in the same way as a large HMO with multiple bathrooms, a cold-water tank and several months of summer vacancy.

That is why a risk-based approach is more useful than simply stamping “valid for two years” on a document.

The practical triggers that mean a review is due

A review is not only about the passage of time. Look for changes that could affect water quality, temperature, flow or tenant exposure.

A new tenancy or change of occupancy

A new tenancy is a useful point to check that the existing assessment still reflects the property and its occupants.

Pay particular attention if the incoming tenant is elderly, immunocompromised or otherwise more vulnerable to serious illness. The water system may not have changed, but the level of potential harm may have.

Property managers and letting agents should build this check into their onboarding process. It is much easier to review a document before move-in than to reconstruct what happened after a complaint.

The property has been empty for a long period

Stagnant water creates additional risk. This is especially relevant for student accommodation, seasonal lets, probate properties and homes awaiting refurbishment.

Before re-letting, outlets should be flushed appropriately and the system checked. You may also need to consider how the property is managed during the void itself, particularly if it remains empty for several weeks or months.

Keep a clear record of the actions taken. “Someone probably ran the taps” is not a record that inspires confidence.

New or modified outlets

Adding a shower, outside tap, hot tub, bathroom or kitchen outlet can alter the water system.

The same applies to changes in pipework, the installation of a water softener or the creation of redundant pipe sections. Any modification that affects water flow, storage or aerosol production should prompt a review.

Showers deserve particular attention because they can create fine water droplets that may be inhaled.

Cold-water tanks and stored hot water

Properties with cold-water storage tanks, hot-water cylinders or other stored water require closer consideration than homes with instantaneous systems.

Check that tanks are properly covered, storage temperatures are controlled and outlets are being used regularly. Stored water and low-use outlets can create conditions where bacteria are more likely to multiply.

An HMO with several bathrooms and a storage system should not be managed using the same assumptions as a small flat with a combi boiler.

Changes to heating or hot-water systems

A new boiler, cylinder, immersion heater or hot-water control system can change the risk profile.

Review the assessment after installation and confirm that temperature controls are working as intended. Stored hot water is generally managed at a temperature high enough to control Legionella, while still considering the risk of scalding. This balance should be addressed by someone competent to assess the system.

What does a professional Legionella risk assessment cover?

A professional legionella risk assessment for rental property should be practical, proportionate and specific to the building. It is not simply a generic form with the address changed.

Depending on the property, the assessment should consider:

• The incoming water supply and how water is stored
• Boilers, cylinders, tanks and temperature controls
• Hot and cold-water outlets
• Showers, hoses, outside taps and other aerosol-producing outlets
• Pipework, redundant sections and possible dead legs
• Water use and occupancy patterns
• Vulnerable residents or users
• The condition of tanks, lids, insulation and fittings
• Periods of vacancy and flushing arrangements
• Existing control measures and recommended actions

The assessor should identify the hazards, consider who may be exposed, evaluate the level of risk and set out proportionate control measures.

Water sampling is not normally required for an ordinary domestic rental property. A temperature check and visual inspection may be more appropriate, depending on the system. A professional assessment is not automatically the same thing as a laboratory test or a “Legionella certificate”.

Good documentation should identify the property, date, assessor, findings, actions and review date. Keep it with your wider property compliance records so your property manager or letting agent can locate it quickly.

What happens if you skip a Legionella risk assessment?

There is no automatic fine simply because you do not hold a document called a Legionella certificate. The HSE does not generally require landlords to produce a specific certificate for domestic properties.

However, that does not remove your responsibility to assess and control the risk.

If a tenant is exposed to Legionella or another water-related hazard, you may need to demonstrate that you took reasonable steps to protect them. A failure to assess or control a foreseeable risk can lead to enforcement action, prosecution, civil claims, reputational damage and potentially serious financial consequences.

The risk becomes particularly difficult to defend if:

• You knew the property had a tank or complex water system
• The home had been empty for a prolonged period
• Tenants reported hot-water or plumbing problems
• The system had been altered without a review
• You had no record of checks, flushing or remedial action

A straightforward assessment and a well-organised record are far easier to manage than a compliance investigation after something has gone wrong.

How Evestaff supports meticulous property management

Evestaff Property Inventory Clerks has been protecting property interests since 2012, giving the team more than 12 years of hands-on experience across London and Kent.

As The Perfectionist, Evestaff focuses on precise, methodical documentation. Highly experienced clerks use modern technology, detailed photographic evidence and structured reporting to give landlords, property managers and letting agents a reliable record of the property’s condition.

An inventory report does not replace a specialist Legionella assessment. It does, however, support a well-managed compliance process by recording fixtures, fittings, visible plumbing features, bathrooms, kitchens and maintenance concerns at key tenancy stages.

Evestaff is also an accredited member of ECMK, reinforcing its commitment to professional standards and quality documentation. If your compliance records are scattered across inboxes, spreadsheets and half-remembered contractor visits, it may be time to bring them into one organised process.

You can learn more about Evestaff’s approach to rental property compliance and detailed documentation or explore property inventory services across London and Kent.

Legionella risk assessment landlords UK: a practical checklist

Use this quick checklist to keep your next review on track:

1. Confirm that every rental property has a documented assessment.
2. Check when it was last reviewed.
3. Identify whether the property has stored water, tanks, cylinders or complex pipework.
4. Record any showers, hot tubs, outside taps and low-use outlets.
5. Check whether the property has been empty for an extended period.
6. Review any changes to tenants, occupancy or vulnerability.
7. Confirm that recommended control measures have been completed.
8. Arrange an earlier review after any significant system change.
9. Keep the assessment with the rest of your property compliance records.
10. Use a competent assessor where the system or risk is beyond your knowledge.

For a typical low-risk home, a two-year review is a sensible working baseline. For higher-risk properties, annual review is often more appropriate. In every case, a significant change means the assessment should be reconsidered sooner.

Frequently asked questions

How long is a Legionella risk assessment valid?

There is no fixed legal expiry period. An assessment remains valid while it accurately reflects the property, water system and occupancy risks.

As good practice, many standard rental properties are reviewed every two years. Higher-risk homes should usually be reviewed annually or whenever circumstances change.

Who can carry out a Legionella risk assessment?

A landlord can assess a straightforward domestic system if they understand the risks and are competent to identify and control them.

You can also appoint a competent professional. This is sensible where the property has tanks, stored hot water, complex pipework, multiple occupants, long void periods or vulnerable tenants.

The person carrying out the assessment should have suitable knowledge, experience and understanding of Legionella risks. The cheapest form is not necessarily the most useful form.

What happens if you do not have a Legionella risk assessment?

You may not receive an automatic penalty simply for lacking a formal certificate. However, you still have a duty to manage health and safety risks.

If a tenant is exposed to Legionella and you cannot show that you assessed and controlled the risk, you may face enforcement action, prosecution, civil claims and reputational damage. Keep a suitable assessment and review it whenever the property or tenancy changes.

Final word for landlords and property managers

The answer to “how often do you need a Legionella risk assessment?” is risk-based, not calendar-based.

Use two years as a practical review point for a standard low-risk rental property. Use annual reviews for higher-risk homes, and always reassess after a new tenancy, long void, plumbing modification or change to the heating and hot-water system.

A meticulous record protects more than a folder. It demonstrates that you have taken your responsibilities seriously.

If you are booking your first Evestaff service, new customers receive 10% off their first booking. And if another landlord or property professional could benefit from the same organised approach, you can casually point them towards the Refer a Friend offer.