Do Landlords Need a Legionella Risk Assessment?

If you let residential property, you have almost certainly been contacted by a company offering a “Legionella certificate” and warning that you are breaking the law without one. The claim is wrong, and the Health and Safety Executive has said so in plain terms. You do have a duty. It is not the duty those letters describe.

This article sets out what the law actually requires of a residential landlord, what the HSE says you can do yourself, and the specific situations where bringing someone in is genuinely warranted.

The short version

Yes, you have a legal duty. It sits in section 3 of the Health and Safety at Work etc. Act 1974, and it requires you to assess and control the risk from Legionella for your tenants.
No, you do not need a certificate. There is no such thing as a legally required Legionella test certificate for a rented home.
You can usually do the assessment yourself. The HSE says so explicitly.
Routine testing of the water is not normally needed in a typical domestic system.
Some properties are different — HMOs with stored water, care settings, and commercial premises. That is where a professional assessment earns its fee.

What the law actually says

The duty comes from health and safety law rather than housing law. The HSE puts it like this:

“Section 3(2) of the Health and Safety at Work Act (HSWA) makes provision for relevant health and safety legislation to apply to landlords to ensure a duty of care is shown to their tenants regarding their health and safety.”
— HSE, Legionella and landlords' responsibilities

So the obligation is real: identify whether there is a risk, and control it. What the law does not do is prescribe a document, a test, or an accredited provider.

Why the risk in most rented homes is low

Legionella bacteria need warmth and time to multiply. They do neither well in a system that is used every day. The HSE's own assessment of ordinary residential property is unambiguous:

“The risks from hot and cold water systems in most residential settings are generally considered to be low owing to regular water usage and turnover.”

A modern house or flat with a combi boiler has no stored water at all, and water that moves is water that does not incubate anything. That is the honest reason most domestic assessments conclude that no further action is needed — and reaching that conclusion, on the record, is what compliance looks like.

The “Legionella certificate” problem

The HSE has addressed the sales practice directly:

“Health and safety law does not require landlords to obtain or produce a ‘legionella test certificate’.”

It also makes clear that testing or sampling the water is only needed in very specific circumstances, which a typical let does not meet. If a letter or a phone call tells you that a certificate is mandatory, or that a test is required annually, the person telling you that is either mistaken or selling you something you do not need.

We would rather say that plainly and lose the enquiry. It is also, for what it is worth, why our Legionella work is aimed at HMOs, commercial premises and care settings rather than at single family lets.

Can you do the assessment yourself?

For a straightforward domestic property, the HSE says you can:

“Most landlords can assess the risk themselves and do not need to be professionally trained or accredited.”

What that assessment needs to cover is the same regardless of who does it. Walk the system and ask:

Is water stored anywhere? A cold water tank in the loft or a hot water cylinder is the main thing that changes the answer. A combi boiler system stores nothing.
Are the temperatures right? Hot water should be stored at 60°C or above; cold water should stay below 20°C. The gap between those two numbers is where Legionella is comfortable.
Are there dead legs? Pipework that leads nowhere — a capped-off run from a removed bathroom, a disconnected outside tap — holds stagnant water indefinitely.
Are there outlets nobody uses? A spare shower, a cloakroom basin, an outside tap in winter.
Is there a shower? Showers create the fine spray that lets the bacteria be inhaled, which is the route of infection. Descaling the head matters more than it sounds.
Will the property stand empty? Void periods are when the risk actually rises, because nothing is moving through the pipes.

Write down what you found and what you did about it. That record is your evidence of compliance — not a certificate from anyone.

What to tell your tenants

Most practical control in a domestic let is carried out by the person living there, so tell them what helps. Run taps and showers that have not been used for a week or two. Keep the shower head clean and descaled. Do not turn the hot water thermostat down below 60°C to save money. Report any problem with the boiler or the hot water rather than living with it.

Put it in the tenancy pack. It takes a paragraph and it is the single most effective control available in an ordinary house.

When you genuinely should bring someone in

The picture changes when the system stops being simple or the people stop being ordinarily healthy:

HMOs and shared houses — stored water serving several units, longer pipe runs, bathrooms added during conversion leaving dead legs behind, and rooms that empty over the summer. We cover HMOs in detail here.
Care homes and supported living — occupants who are older, immunosuppressed or otherwise more susceptible to infection, plus blended-temperature outlets that sit in the risk range by design.
Commercial premises — where you are an employer or in control of premises, the Approved Code of Practice applies to you directly. ACOP L8 explained here.
Cooling towers, evaporative condensers and spa pools — a different order of risk entirely, with a separate notification duty.
Large or unusual systems — multiple tanks, long runs, buildings that have been extended repeatedly, or anywhere the pipework is no longer understood.

What this means in practice

Do the assessment. Write it down. Review it when something changes — a new boiler, a bathroom removed, a long void. Give your tenants the paragraph about running the taps. For an ordinary house or flat, that is the whole of your duty, and it costs nothing but an hour.

If your property is an HMO, a care setting or a commercial building, the honest answer is different, and that is the work we do.

Frequently Asked Questions

Do landlords legally need a Legionella risk assessment?

Yes. Section 3 of the Health and Safety at Work etc. Act 1974 places a duty on landlords to assess and control the risk from Legionella for their tenants. But the HSE states that most landlords can assess the risk themselves and do not need to be professionally trained or accredited, and that the risks in most residential settings are generally considered to be low because of regular water usage and turnover.

Is a Legionella certificate a legal requirement for landlords?

No. The HSE states directly that health and safety law does not require landlords to obtain or produce a 'legionella test certificate'. There is no such statutory document for a rented home. Companies selling one as a legal necessity are misrepresenting the position. What the law requires is that you assess the risk and control it, and that you can show you did.

Do I need to have the water tested for Legionella?

Not in a typical domestic property. The HSE says testing or sampling for Legionella is only needed in very specific circumstances, which an ordinary house or flat does not usually meet. Control in domestic systems is achieved through temperature, water turnover and removing stagnation, not through routine sampling.

Can I carry out the Legionella risk assessment myself?

For a straightforward domestic property, yes — the HSE says most landlords can assess the risk themselves. You need to identify whether water is stored, whether hot water is at 60°C or above and cold water below 20°C, whether there are dead legs or unused outlets, and what happens during void periods. Record what you found and what you did about it.

What temperatures should hot and cold water be kept at?

Where temperature is used as the control, hot water should be stored at 60°C or above and reach at least 50°C at the outlet within a minute of running. Cold water should be maintained below 20°C. Legionella multiplies in the range between those two figures, which is why keeping hot water genuinely hot and cold water genuinely cold is the primary control.

How often should a domestic Legionella risk assessment be reviewed?

There is no fixed statutory interval. Review it whenever something changes that could affect the water system — a new boiler or cylinder, a bathroom added or removed, a change in occupancy, or after a long void period. Many landlords review every two years as a matter of routine, which is reasonable but not a legal requirement.

Which properties genuinely need a professional assessment?

HMOs and shared houses with stored water, longer pipe runs and seasonal voids; care homes and supported living, where occupants are more susceptible and blended-temperature outlets sit in the risk range; commercial premises, where the Approved Code of Practice L8 applies directly; and anywhere with cooling towers, evaporative condensers or spa pools, which carry a separate notification duty.

What should I tell my tenants about Legionella?

Give them a short written note: run taps and showers that have not been used for a week or more, keep the shower head clean and descaled, do not turn the hot water thermostat below 60°C, and report any problem with the boiler or hot water. In an ordinary rented home, tenant behaviour is the most effective control available.

Do Landlords Legally Need a Legionella Risk Assessment?