In brief
- HSE says landlords have a duty to assess the risk from legionella, but a detailed assessment is not required for a typical domestic let.
- HSE says most landlords can do the assessment themselves and do not need to be professionally trained or accredited.
- There is no legal requirement for a 'legionella test certificate', and routine water testing is not usually required for domestic systems.
- HSE says to keep hot water hot (stored at 60°C), cold water cold and water moving, and to flush the system before letting.
- In Scotland the Repairing Standard guidance says to assess before the first let and review at least every two years.
Yes. If you let out a home you must assess the risk of legionella in its water system. For an ordinary rental that usually means a short, simple assessment that you can do yourself, not a certificate or routine water testing. Pay a professional when the plumbing is complex or the property is shared.
That short answer is the one most landlords want, and it matches what the Health and Safety Executive (HSE) says on its landlord page. What the sales pages for assessors tend to leave out is how light the legal requirement is for a normal house or flat, and what a sensible landlord does with that freedom. This guide covers the law, the competence question, a checklist for a simple domestic assessment, the cases where paying for help makes sense, and the position in Scotland, Wales and Northern Ireland.
If you only want the money side, see our guide to legionella risk assessment cost. For the wider picture of what a landlord has to keep up to date, the legionella hub and the landlord certificates checklist are the places to start.
Do landlords need a legionella risk assessment?
Yes, in the sense that matters. HSE’s guidance for landlords says you have a duty to assess the risk from exposure to legionella, and that this does not require an in-depth, detailed assessment. The duty comes from the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health Regulations (COSHH), which cover biological agents such as legionella. HSE’s Approved Code of Practice, known as L8, and its technical guidance HSG274 Part 2 on hot and cold water systems sit behind that.
Who counts as a landlord for legionella purposes?
HSE defines a landlord as anyone who rents out a property they own under a lease or licence shorter than seven years. That catches private landlords, councils, housing associations and housing co-operatives. It also catches someone renting out a room in their own home. A letting agent managing the property for you does not take the duty off you; it is worth asking the agent in writing what they do and what they record.
Why the risk is usually low in a normal home
Legionnaires’ disease is a potentially fatal form of pneumonia. HSE explains that people catch it by breathing in tiny airborne droplets of water containing the bacteria, and that it is not known to spread from person to person. The bacteria grow when water sits between 20 and 45°C, when it is stored or recirculated, when it can be sprayed into the air (a shower, for example) and when it contains deposits such as scale or rust.
HSE says the risks from hot and cold water systems in most residential settings are generally considered to be low. The risk is lowest where water is used daily, cold water comes straight from the mains, and hot water comes from an instantaneous heater or a low-volume heater such as a combi boiler. A simple assessment might well conclude that no further action is needed. It is still an assessment, and it still has to be looked at again if something changes.
Do I need a legionella certificate or a water test?
No. HSE states that landlords are not required to obtain or produce a legionella test certificate, and that routine testing is not usually required for domestic systems. Temperature monitoring is the reliable way to confirm that the system is under control. If someone tells you that you must have a certificate to let your property, they are describing a commercial product, not a legal rule. Gas and electrical safety are different: those do come with certificates and fixed dates, and you can see them side by side in our landlord certificates checklist.
When sampling does make sense
HSE’s page on testing and monitoring says that hot and cold water systems do not usually need routine microbiological monitoring, but testing may be needed if the effectiveness of the control regime is in doubt, or if recommended temperatures are not consistently met. Where you do test, HSE says samples should go to a UKAS-accredited laboratory that takes part in a water microbiology proficiency testing scheme, and that sampling should follow BS 7592. A kit bought online and posted off is not a substitute for an assessment of the system, because a single sample tells you about one outlet on one day.
Do I have to write the assessment down?
Not as a landlord, strictly. HSE says recording the assessment is a statutory duty for employers with five or more employees, which most landlords are not, but that keeping a record is advisable. We would keep one anyway. If a tenant ever becomes ill and you are asked to show what you did, a dated page saying what you checked and what you found is a good deal better than a recollection. HSE makes the same point about enforcement: inspectors do not proactively inspect domestic premises or ask for evidence of risk assessments, but a landlord could face prosecution if a tenant caught Legionnaires’ disease from the home’s water system, and would need to show a court they had met their duty.
Can a landlord do their own legionella risk assessment?
Yes. HSE says most landlords can assess the risk themselves and do not need to be professionally trained or accredited. If you lack the competence, or simply the inclination, you can arrange for someone else to do it. HSE does not make accreditation a condition for assessing your own simple system.
What competence means in practice
HSE’s wording is relaxed, but the word competence is doing real work. In our reading, you are competent to assess a simple domestic system if you can do four things:
- work out what type of hot water system the property has (combi boiler, hot water cylinder, immersion heater, electric shower, a loft cold water tank or none)
- find the places where water can sit still or stay lukewarm: rarely used taps and showers, redundant pipework, dead ends, an uncovered tank
- check temperatures with a thermometer rather than guessing
- explain to a tenant, in plain words, what they need to keep doing
If any of those is beyond you, or you would rather not carry the responsibility, that is the point at which to hire someone. If you are unsure about a particular home, working through the checklist below will usually show you quickly whether you are in simple territory or not.
What does a simple legionella risk assessment look like for a rented home?
HSE does not publish a form for landlords, and it would be wrong for us to pretend that one layout is the official one. What HSE does set out is the content: understand the system, control the risk with temperature and use, tell the tenants, and review. The checklist below turns that into something you can complete on one visit to a typical house or flat. We have flagged where a point comes from HSE and where it is our own practical suggestion.
| What to check | What good looks like | Source |
|---|---|---|
| Type of hot water system | Note whether it is a combi or instantaneous heater, or a cylinder (calorifier) with stored hot water | HSE: low-volume or instantaneous systems are lower risk |
| Hot water storage temperature | Cylinder set so water is stored at 60°C | HSE landlord page |
| Hot water at the taps | Reaches 50°C at outlets (HSE says within one minute on its hot and cold water page) | HSE |
| Cold water | Kept below 20°C where possible; cold tanks, if fitted, covered with a tight-fitting lid | HSE |
| Redundant pipework and dead ends | Identified and removed, or at least noted | HSE |
| Rarely used outlets | Spare bathroom, en suite or outside tap flushed at least weekly | HSE says weekly use for vacant property; weekly for rarely used outlets is our suggestion |
| Showers | Tenant told to clean and disinfect showerheads regularly; electric instantaneous showers are lower risk | HSE |
| Flushing before a let | All outlets run through before a new tenant moves in | HSE |
| Tenant instructions | Do not change the cylinder thermostat; report hot water that does not heat properly | HSE |
| Written note and review date | One page, dated, with what you found and what you did | Advisable per HSE; the format is ours |
Step by step on the day
- Draw the system. A sketch is enough: boiler or cylinder, any tank, bathrooms, kitchen, any outside tap. Mark anything that looks unused.
- Take temperatures. Use a probe or digital thermometer at the hot tap furthest from the heater, and at a cold tap after running it for a minute or two. Write the numbers down.
- Look for stagnation. Find taps and showers that nobody has run recently, and any pipework that goes nowhere.
- Look at the storage. If there is a cold water tank, check the lid, the cleanliness and the insulation. If there is a cylinder, check its thermostat setting.
- Decide the risk. For a combi-heated flat with mains-fed cold water and every outlet used daily, the honest answer may be low risk with no action. Say so on the page.
- Brief the tenant. Give them the three or four instructions in the table. Put them in the tenancy information pack or an email so there is a record.
- Set a review. Put the date, and the triggers below, in your renewal calendar.
How do you control legionella risk in a rental property?
HSE’s summary is easy to remember: keep the hot water hot, the cold water cold, and keep it moving. For most landlords the controls come down to a handful of habits.
Temperature
HSE says temperature control is the most reliable measure for most domestic systems. Set the cylinder so that water is stored at 60°C, and where low-volume heaters supply the outlets, they should deliver water at 50°C. A higher storage temperature means water at the tap can scald, and HSE flags a scalding risk above 44°C at baths and showers, so temperature control and scald protection go together. If you are unsure how to square the two in a particular bathroom, ask a plumber about the mixing arrangements; do not turn the cylinder down to make it feel safer.
Movement
Water that sits still in a pipe warms up to room temperature, and that is the condition the bacteria like. Dead legs (pipes to outlets that are unused or rarely used) and dead ends (redundant pipe closed at one end) are the classic trouble spots, according to HSE. In a house that has been altered over the years, it is common to find a capped pipe from a removed basin or radiator. Have it removed back to the live pipe.
Tanks and showers
If there is a cold water tank, HSE says it should be covered with a tight-fitting lid to stop debris getting in. Showers create the aerosol that is the route of infection, which is why HSE asks tenants to clean and disinfect showerheads regularly. Instantaneous electric showers pose less risk because they are cold water fed and heat only a small volume at a time.
Telling the tenant
HSE’s list of what tenants need to know is short: do not change the temperature setting on the cylinder, clean showerheads regularly, and tell the landlord if hot water is not heating properly or something else seems wrong. Your tenant is the one who will notice a cylinder that has stopped heating. Make it easy for them to tell you.
What about empty properties and void periods?
This is where a good landlord can go wrong without noticing. A house that stands empty for a month between tenants has every tap and shower stagnating. HSE says water must not be allowed to stagnate, that outlets should be used at least once a week in a vacant property, and that for a long vacancy you should use a suitable flushing regime or drain the system down.
A practical routine is to ask the agent, a neighbour or a cleaner to run each tap and shower for a couple of minutes once a week, and to log it. Before the next tenant moves in, flush the whole system, as HSE advises. Keep the note with the file, because a void period is one of the triggers for reviewing the assessment.
When should a landlord pay for a professional legionella risk assessment?
Because HSE allows a light-touch assessment for a typical domestic let, the sensible question is not whether you are required to pay, but whether your property is typical. The table sets out the situations where we would think hard about a professional. These are our judgement, not HSE rules, and HSE’s landlord page does not single out any of them.
| Situation | Why it raises the stakes |
|---|---|
| HMO or house share with several bathrooms | More outlets, more showers, more occupants and more chances for an unused or lukewarm outlet. HSE’s landlord guidance applies to all landlords and does not exempt shared houses |
| Cold water tank or large hot water cylinder you cannot see into or never touch | Stored water is where the bacteria multiply when it is neither hot nor cold enough |
| Showers or taps that are rarely used (en suite, guest room, annexe) | Dead legs and stagnation, plus the aerosol from a shower |
| Frequent or long void periods, holiday or short lets | Water sits unused; a regular flushing routine has to be run by someone |
| Block or converted house with shared plumbing or communal tanks | You may control the shared system but not each flat; one assessment must cover the whole supply |
| Hot water that will not reach 60°C in the cylinder or 50°C at the taps | A temperature failure is a control failure; a plumber and an assessor may both be needed |
| You are unsure, or a tenant or the council has raised a concern | Paying for a second pair of eyes is cheap compared with being unable to show what you did |
None of this means the professional route is the only route. It means that if the system has a cylinder, a tank, a spare shower and a history of voids, you are no longer in the simple case HSE describes, and a written assessment by someone who does this daily is good value. Your letting agent, lender or insurer may have conditions of its own; we have not verified what any of them require, so check rather than assume.
How to choose an assessor
We found no statutory licence for domestic legionella assessors on the pages we read, and HSE says landlords do not need to be accredited to assess their own simple systems. If you hire someone, ask what qualifications and experience they have with domestic and shared housing, whether they will visit and take temperatures rather than send a template, what the written report will contain, and whether they will tell you what to do when the system is out of range. The Legionella Control Association runs an online directory of members who comply with its Code of Conduct and Service Standards; we could not confirm from its site how many members cover domestic landlord work, so ask. Our find a professional tool lists how to look for assessors by area.
How much does a legionella risk assessment cost?
A self-assessment costs your time and a thermometer. The published prices we found in October 2026 for a professional assessment of a standard domestic let were in the tens to low hundreds of pounds, with HMOs and larger systems costing more. Those were cost guides and provider pages, not our own survey, and they vary. The detail, with the sources and the cost of laboratory sampling, is in our guide to legionella risk assessment cost.
How often should a legionella risk assessment be reviewed?
In England and Wales the law sets no fixed interval. HSE says the law does not prescribe that the risk assessment is reviewed on an annual or two-yearly basis, and that you should review it periodically in case anything changes. If access to occupied units is difficult, HSE says checks can be made during visits you are making anyway, such as gas safety checks or routine maintenance. That is helpful: you can pair the legionella look-round with the annual gas safety check.
| Trigger | What to do |
|---|---|
| New boiler, cylinder, tank or bathroom | Update the system description and temperatures |
| Property empty for more than a week or two | Flush before the next let and note it |
| New tenant | Re-brief them and check the shower and hot water on the move-in visit |
| Hot water complaint or a tenant who is unwell | Check temperatures straight away; get an assessor if you cannot find the cause |
| Nothing has changed | A periodic look; many landlords pick an annual date. In Scotland, at least every two years (see below) |
What happens if a tenant gets Legionnaires’ disease?
HSE says that if a tenant contracts Legionnaires’ disease from the home’s water system, the landlord may face prosecution under the Health and Safety at Work etc. Act and would need to show a court that they had met their legal duty. That is the practical reason to write a short note even though HSE says you do not strictly have to. The offences and penalty ranges under the Act are set out in the Act’s own schedules; we have not summarised them here because they depend on the section charged, and we would rather link than guess.
Legionella rules in England, Wales, Scotland and Northern Ireland
| Nation | Position |
|---|---|
| England | HSE’s landlord guidance applies in Great Britain: assess the risk, light-touch for a typical home, no certificate, review if the system changes. Housing standards add to this through the Housing Health and Safety Rating System, but we did not find legionella-specific council rules for private lets |
| Wales | The same HSE guidance applies in Great Britain. Wales also has its own fitness for human habitation regulations for rented homes; we did not find legionella named as a separate requirement in the pages we read |
| Scotland | HSE’s guidance applies, and the Scottish Government’s Repairing Standard statutory guidance for private landlords says landlords have a duty to carry out a risk assessment of hot and cold water systems for legionella, that all water systems must be assessed before the property is first let, and that the assessment should be reviewed at intervals of no more than two years. It also says to flush the system before letting if it has not been flushed in the previous two years, store hot water at 60°C or above, remove redundant pipework and dead ends, tell tenants about the control measures, and prevent stagnation in vacant property |
| Northern Ireland | The Health and Safety at Work (Northern Ireland) Order 1978 and the COSHH Regulations (Northern Ireland) 2003 apply, and HSENI points to L8 for practical guidance. We did not find HSENI guidance written specifically for domestic landlords, so check with HSENI or your council |
The Scottish difference is worth noting because it is a rare case of a stricter written rule than in England. A Scottish landlord should assess before the first let, keep to the two-year review, and be ready to show the note. An English landlord would be wise to adopt the same habit.
Next steps
Walk the property with a thermometer and the checklist above, write a one-page note, set a review date and brief your tenant. If you find a system with stored water, rarely used outlets or a long list of voids, get a quote from an assessor and compare it with the effort of putting it right yourself. The compliance checker shows what else your property needs, and the legionella hub gathers the rest of this cluster.
This guide explains the rules as published on 30 October 2026; for a specific property, check with your local council or a qualified professional.
Questions landlords ask
Do landlords need a legionella risk assessment?
Yes. HSE says landlords have a duty to assess the risk from legionella, but that this does not require an in-depth, detailed assessment for a typical domestic property. A simple assessment may conclude that no further action is needed. It should be reviewed if the water system changes. In Scotland the Repairing Standard guidance says to assess before the first let.
Can I do my own legionella risk assessment as a landlord?
Yes. HSE says most landlords can assess the risk themselves and do not need to be professionally trained or accredited. If you lack the competence or inclination, you can arrange for someone else to do it. For a shared house, stored hot water, rarely used showers or long voids, a professional is more sensible.
Do I need a legionella certificate to rent out a property?
No. HSE says landlords are not required to obtain or produce a legionella test certificate, and routine testing is not usually required for domestic hot and cold water systems. What you need is a risk assessment, sensible temperature control and flushing, and ideally a short dated note of what you did.
How often should a legionella risk assessment be done for a rental property?
England and Wales have no fixed interval: HSE says the law does not prescribe annual or two-yearly reviews, only that you review it if anything changes. Scottish Repairing Standard guidance says to review at intervals of no more than two years. Review sooner after a new boiler, cylinder or bathroom, or a long void.
What temperature should hot water be to prevent legionella?
HSE says to set the hot water cylinder so water is stored at 60°C, with low-volume heaters supplying outlets at 50°C, and to keep cold water below 20°C where possible. Keep the water moving by using every outlet at least weekly in a vacant property, and flush the system before letting.
Harriet Lowe, keeper of renewal dates. This guide explains the rules as published on 30 October 2026. Spotted a change? Tell us.
Sources, checked on 30 October 2026
- HSE: Legionella and landlords' responsibilities
- HSE: Legionnaires' disease. The control of legionella bacteria in water systems (L8)
- HSE: Hot and cold water systems
- HSE: Testing and monitoring your water system for legionella
- HSE: What is Legionnaires' disease?
- Scottish Government: Repairing Standard statutory guidance for private landlords, Annex D1 (installations for the supply of water)
- HSENI: Legionella
- Legionella Control Association