Is it the same as a legionella test?

No. A test sends a water sample to a laboratory and reports what was in it that day. HSE says testing is not usually required for domestic hot and cold water systems. The assessment looks at whether the system could let bacteria grow at all.

Is it a legal requirement for landlords?

Yes. Health and safety law requires landlords to assess and control the risk of exposure of tenants to legionella. There is no certificate in law and no prescribed form; for most rented homes a simple assessment is enough.

Who can carry it out?

Anyone competent. HSE expects most landlords to be able to assess a simple domestic system themselves, or to have a letting agent’s staff or a contractor do it. DwellFlow guides the person doing it and the AI produces the documents.

How long does it take and what does it cost?

Thirty minutes to an hour at the property, depending on the size and type of the water system. A firm that visits charges £75 to £150; doing it yourself with DwellFlow costs £20 including VAT.

What comes out of it?

A record: the assessment with its findings and actions, a written scheme of control saying what will be done routinely, and something for the tenant. Reviewed when the system, its use or the occupants change.

The plain explanation

What is a legionella risk assessment?

A written look at a property’s hot and cold water system to find where legionella bacteria could grow and be breathed in, what will be done about it, and who will do it. For a rented home it is a legal duty on the landlord. It is not a test and not a certificate, and most landlords can do it themselves.

The bacteria, briefly

Warm, still water, and a shower to breathe it in.

Legionella is a bacterium that lives in water. Legionnaires’ disease is, in HSE’s words, “a potentially fatal form of pneumonia”, caught “by inhaling small droplets of water (aerosols), suspended in the air, containing the bacteria”. In a house the droplets come from showers and spraying taps. The bacteria multiply in water between 20 °C and 45 °C, in water that is stored or stands still, and where there are deposits to feed on: rust, sludge, scale. The people most at risk are over 45, smokers and heavy drinkers, and anyone with a lung, heart or kidney condition, diabetes or a weakened immune system. HSE’s own explanation is here.

What the assessment does

Three questions, answered in writing.

Where could the bacteria grow? How the water is stored and heated; the temperature at every outlet; outlets that are rarely used; a tank without a lid; a cylinder that never gets hot enough; a property that stands empty.
Could anyone breathe it in? Showers, spray taps, who lives there and whether any of them are in the groups most at risk.
What will be done, and by whom? For each thing found, the fix and the date. And the routine that keeps the risk down week to week: the written scheme of control.

Then it is written down, with photographs, and dated, and it is looked at again when the system, its use or the occupants change.

What it is not

Not a test, not a certificate, not a form with ticks.

Not a test. A laboratory sample says what was in the water on one day. HSE says testing “is not usually required for domestic hot and cold water systems”.
Not a certificate. HSE: health and safety law “does not require landlords to obtain or produce a ‘legionella test certificate’”. Anyone selling one is selling a piece of paper.
Not a form with ticks. A box marked “hot water satisfactory” is not an assessment. A reading, a photograph and an action are.
Not once and done. It is reviewed, regularly and whenever there is reason to think it no longer holds.

The landlord facts are on HSE’s page on legionella and landlords’ responsibilities.

Who does it

Anyone competent. That can be you.

HSE expects most landlords to be able to assess a simple domestic system themselves, without professional training. The difficulty was never the visit; it was knowing what to look at, what the numbers mean, and what to write. DwellFlow does that part: your phone asks the questions at the property, you take the readings and the photographs, the AI checks the survey before you submit and then does the write-up. Thirty minutes to an hour, £20 a property including VAT. Or your letting agent’s inspector does it on a visit they already make.

Questions people ask

Short answers.

What is a legionella risk assessment? A written look at a property’s hot and cold water system to find where legionella bacteria could grow and be breathed in, what will be done about it and who will do it. It records how the water is stored and heated, a temperature at every outlet, the risks found, the actions, and the routine that keeps the risk down.
Is it the same as a legionella test? No. A test sends a water sample to a laboratory and reports what was in it that day. HSE says testing is not usually required for domestic hot and cold water systems. The assessment looks at whether the system could let bacteria grow at all.
Is it a legal requirement for landlords? Yes. Health and safety law requires landlords to assess and control the risk of exposure of tenants to legionella. There is no certificate in law and no prescribed form; for most rented homes a simple assessment is enough.
Who can carry it out? Anyone competent. HSE expects most landlords to be able to assess a simple domestic system themselves, or to have a letting agent’s staff or a contractor do it. DwellFlow guides the person doing it and the AI produces the documents.
How long does it take and what does it cost? Thirty minutes to an hour at the property, depending on the size and type of the water system. A firm that visits charges £75 to £150; doing it yourself with DwellFlow costs £20 including VAT.
What comes out of it? A record: the assessment with its findings and actions, a written scheme of control saying what will be done routinely, and something for the tenant. Reviewed when the system, its use or the occupants change.