Landlord guide

Reviewed 18 August 2026

Is a Legionella risk assessment a legal requirement for landlords?

This is the question landlords most often ask, and the answers online tend to blur two very different things: a legal duty to assess and control risk, and a document that somebody sells you. Only the first exists in law.

Below is what the duty actually requires, who it falls on, how it differs in Northern Ireland and the Republic of Ireland, and what a proportionate response looks like for a house or flat.

The short answer

Yes — if you let residential property in Great Britain you have a legal duty to identify, assess and control the risk from Legionella bacteria in the water system, under the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health Regulations 2002.

No — there is no statutory Legionella certificate, no prescribed government form and no requirement to appoint a third-party assessor for a straightforward domestic system.

The HSE's position is that most simple domestic water systems are likely to be low risk, so the assessment should be short and proportionate rather than elaborate.

General information, not legal advice. This guide describes the position in Great Britain. Northern Ireland is regulated by HSENI, and the Republic of Ireland has a separate legal framework — see the country pages.

Where the duty comes from

In Great Britain the duty rests on general health and safety law rather than on a Legionella-specific statute. The Health and Safety at Work etc. Act 1974 places duties on people in control of premises in connection with a trade or business, and letting property is treated as such an undertaking. The Control of Substances Hazardous to Health Regulations 2002 then require the risk from a biological agent — here, Legionella bacteria — to be assessed and controlled.

The HSE's Approved Code of Practice L8 and the accompanying HSG274 guidance explain how to do that in practice. An Approved Code of Practice has a particular status: you do not have to follow it, but if you are prosecuted and did not follow it, you must show you achieved the same standard another way.

What the duty asks you to do

Understand the water system in the property: how water arrives, how it is heated, whether any is stored, and where it can sit still
Identify what could allow Legionella bacteria to multiply, such as warm stagnant water, sediment, scale or debris
Identify how anyone could be exposed to a breathable spray, most commonly from showers
Put in place and maintain sensible controls that are proportionate to the risk you found
Review the assessment periodically and whenever something relevant changes

Is a certificate legally required?

No. The HSE states plainly that health and safety law does not require landlords to obtain a Legionella test certificate. Products marketed as a "landlord Legionella certificate" are commercial documents, not statutory ones.

What is expected is that you can show the risk was assessed and is being managed. A structured Legionella risk assessment report does that far better than a certificate, because it records the system, the findings and the actions rather than simply asserting an outcome.

Do you have to write it down?

The formal duty to record significant findings is qualified — it does not fall on every individual landlord in exactly the same way, and the HSE recognises that many domestic assessments are simple. That is a technical point about the letter of the law, not a reason to keep nothing.

In practice a written record is the only realistic way to show that a competent assessment happened, to hand information to a tenant or agent, to know what to check at the next review, and to see what changed since last time. Keeping a record is prudent and useful, and costs almost nothing once the work has been done.

Who holds the duty?

The duty follows control of the premises. A landlord managing their own lettings holds it directly. Where a managing agent takes on maintenance and compliance, the written management agreement should state clearly who carries out the assessment, who acts on findings and who keeps the record.

An agent does not automatically assume the landlord's legal duty simply by managing the property. Allocate it explicitly in writing, and make sure the landlord holds a copy of the record either way.

How the position differs across the UK and Ireland

England: HSE-regulated duty under HSWA and COSHH. Housing condition is judged separately under housing legislation.
Scotland: Same HSE-regulated duty. The Repairing Standard and the model private residential tenancy notes also bring Legionella into the tenancy relationship.
Wales: Same HSE-regulated duty, alongside the fitness for human habitation requirements that apply to occupation contracts.
Northern Ireland: Equivalent duties apply, but the regulator is HSENI rather than the HSE, and the enabling legislation is the Northern Ireland order-making framework.
Republic of Ireland: A separate legal framework entirely. UK ACOP L8 does not apply — see the Republic of Ireland page for the relevant Irish sources.

What a proportionate response looks like

For a two-bedroom flat with a combi boiler, the assessment might be a single visit: describe the system, list the outlets, note the shower and any little-used tap, take and record the observations you can take safely, note anything that needs attention, tell the tenant to run outlets after a period away, and set a date to look again.

For a converted building with a shared cold-water tank, communal plant or a stored hot-water system serving several flats, the picture is different and the work usually belongs with a competent specialist or with whoever controls the shared plant.

Questions landlords also ask

Can I be fined for not having a Legionella risk assessment?

Health and safety duties are enforceable, and enforcement action follows serious failures to assess or control risk. The practical point is not the penalty but the position it leaves you in: without an assessment you have no basis for saying the risk in your property was understood or managed.

Does the duty apply to a single buy-to-let?

Yes. Letting property is treated as an undertaking, so the duty applies whether you let one flat or a hundred. What changes with scale is the effort involved, not whether the duty exists.

Does it apply to a holiday let or short-term let?

The duty applies to premises you control in connection with your business. Short-let properties often carry a higher stagnation risk because they sit empty between guests, so the assessment should look closely at void periods and little-used outlets.

Is a Legionella risk assessment required before every new tenancy?

There is no rule requiring a fresh assessment for each tenancy. A change of occupancy is, however, a sensible moment to check the existing assessment still describes the property, and to deal with any stagnation from the void.

See whether guided self-assessment fits your property

The free suitability check asks a short set of questions about the water system, the building and the occupants, then tells you plainly whether guided self-assessment looks appropriate or whether the property should go to a specialist.

Check if my property is suitable See how LegionellaWise works

Official sources

General information, not legal advice. Requirements and guidance differ between jurisdictions — check the country page that applies to your property.