How to do a Legionella risk assessment on a rental property
Most published Legionella checklists are either a two-line box-tick or a template written for a hospital. Neither helps a landlord with a flat and a combi boiler.
The sequence below is the one we use in the product, and it works just as well on paper. It is written for a simple domestic hot and cold water system in a house or self-contained flat.
The short answer
Work through the property in a fixed order: check the assessment is suitable for you to do, describe the water system, understand who uses it, register every outlet room by room, look for stagnation and poor condition, record the observations you can take safely, then turn what you found into findings, actions and tenant information.
Finish by deciding what would trigger a review, and write the whole thing down while it is fresh.
This is a process, not a substitute for competent judgement. If the system or the findings go beyond what you can confidently interpret, refer the property to a specialist.
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.
Before you start: is this assessment suitable for you to do?
Competence is about the person and the specific system, not about having a form. Ask honestly whether you understand how water is heated, stored and distributed in this property, whether you can recognise a dead leg or a poorly sited tank, and whether you can interpret an unexpected reading.
If the property has communal plant, a shared cold-water storage tank, a large or complex stored hot-water system, or occupants who are particularly vulnerable to infection, the assessment should go to a competent specialist. Using software does not make anyone competent — it structures the work of someone who is.
The nine steps
- 1
Confirm suitability and competence
Decide whether the system is simple enough for guided self-assessment and whether you are competent for it. Record that decision and your reasons.
- 2
Describe the water system
Note the incoming supply, how hot water is produced (combi, unvented cylinder, vented cylinder, electric shower), whether hot or cold water is stored, tank locations and condition, and roughly how the pipework runs.
- 3
Understand occupants and exposure
Note how the property is occupied and how anyone could inhale a fine spray. Showers are the main exposure route in a home; spray taps, hose attachments and garden sprayers matter too.
- 4
Build a room-by-room outlet register
Walk the property and list every outlet: basins, baths, kitchen taps, showers, utility taps, outside taps and anything disconnected but still plumbed. Note which are used daily and which are little used.
- 5
Look for storage, dead legs and stagnation
Check tanks for lids, insulation, debris and warmth. Look for capped or redundant pipework, unused en-suites, guest bathrooms, and outlets that only get used when someone visits.
- 6
Record temperatures and observations
Where it is practical and safe, run the outlet and record hot and cold readings with the outlet and date they belong to. Note where an outlet is blended through a thermostatic mixing valve, because that changes what the reading means.
- 7
Capture evidence
Photograph the thermometer at the outlet, the cylinder or tank, and anything unusual. Keep each photo attached to the observation it supports rather than in a general folder.
- 8
Turn observations into findings and actions
Each concern becomes a finding with a plain-language action and an owner. "Shower head scaled" becomes "descale or replace shower head", not a note in the margin.
- 9
Give the tenant information and set review triggers
Tell the tenant what to do after a period away, why not to interfere with the boiler thermostat, and to report problems. Then write down what would make you reassess.
What to look for room by room
Bathrooms and en-suites
The shower is usually the highest-exposure point in a domestic property because it produces a fine, breathable spray. Look at the head and hose for scale and biofilm, and note when the room was last used — a guest en-suite used twice a year is a stagnation risk even in a low-risk property.
Kitchen and utility
Kitchen outlets are usually used daily, which helps. Check the cold tap runs genuinely cold after a short run, and note appliances plumbed in with long flexible fills.
Airing cupboard, loft and outside
If there is a cylinder, note its type, thermostat setting where visible and general condition. If there is a cold-water storage tank, note whether it has a close-fitting lid, whether it is insulated and whether the water looks clean. Outside taps and hose reels are commonly overlooked and often stagnant.
What to write down
- The date, the property and who carried out the assessment
- The system description, including whether hot water is stored
- The outlet register with usage frequency for each outlet
- Observations and readings tied to a named outlet
- Photographs attached to the finding they support
- Each finding, the action, who owns it and whether it is done
- Information given to the tenant
- The review trigger and the date you intend to look again
Common mistakes
- Recording a single "hot water: 55°C" for the whole property instead of per-outlet readings
- Missing the outside tap, the loft tank or a disconnected but still-plumbed pipe
- Treating a blended outlet reading as if it showed the hot water distribution temperature
- Listing a finding with no action, or an action with no completion date
- Copying an assessment from another property with the address changed
How LegionellaWise structures the same process
The product runs this sequence as a guided workflow: a suitability check first, then a system description that changes which prompts you see, a room-by-room outlet register, guided measurements with the thermometer photo attached to the reading, and completeness checks before anything can be finalised.
The output is a structured, versioned Legionella risk assessment report with the findings, actions and evidence in one place, plus a review reminder on a date you choose. It organises and records competent work; it does not replace the judgement behind it.
Questions landlords also ask
How long does a landlord Legionella risk assessment take?
For a simple flat or house, walking the property and recording the outlets and observations typically takes well under an hour. Complex systems take longer and often need a specialist.
Is there an official HSE template I should use?
There is no official HSE Legionella risk assessment template for landlords. The HSE describes what the assessment must cover and leaves the format to you, which is why a property-specific record is more useful than a generic blank form.
Do I need to enter the property to do it?
Yes. You cannot describe a water system, list outlets or observe condition without seeing them. Arrange access with the tenant and give proper notice.
What if I find something I do not understand?
Stop and get advice. An unexpected reading, an unexplained tank, discoloured water or evidence of a system you cannot account for are all reasons to bring in a competent specialist rather than guess.
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.
Official sources
- HSE — Identify and assess sources of risk
- HSE — Legionella and landlords' responsibilities
- HSE — Hot and cold water systems
- HSE — Approved Code of Practice and guidance L8
General information, not legal advice. Requirements and guidance differ between jurisdictions — check the country page that applies to your property.
Related reading
Water temperatures
Common HSE reference points for hot and cold water, what a reading does and does not prove, and how to record one properly with TMV and scalding caveats.
Can I do it myself?
A decision guide built around competence and system complexity, with plain examples of when self-assessment fits and when to use a specialist.
Combi boiler properties
No stored hot water usually lowers the risk, but it does not remove the duty to assess — or the risks from stagnation, showers and little-used outlets.
Empty properties and voids
Stagnation during voids, pre-tenancy checks, flushing without creating unnecessary spray, and what to document before a new tenant moves in.