Legionella Risk Assessment for Landlords: Cost and Whether You Need One
A professional legionella risk assessment costs £60 to £120 for a typical flat or house in 2026, and £100 to £180 for an HMO or a house with stored water tanks. You may not need to pay at all: the Health and Safety Executive says most landlords can assess a simple domestic system themselves, no legionella certificate exists in law, and there is no fixed renewal date. The duty is real, though: under the Health and Safety at Work Act 1974 and COSHH, every landlord in England must assess and control the risk of Legionnaires' disease from a rental's water. This guide covers the law, a do-it-yourself checklist, when to pay a professional, the cheap controls, and what happens if a tenant falls ill with no assessment on file.
In this guide
Do landlords need a legionella risk assessment? There is no legionella certificate for landlords Legionella risk assessment cost by property type and region What a legionella risk assessment covers How to do your own legionella risk assessment Controls that cost almost nothing When to review the assessment If a tenant contracts Legionnaires' disease and there is no assessment Frequently asked questions SourcesDo landlords need a legionella risk assessment?
Yes, in the sense that every landlord has a legal duty to assess the risk. No, in the sense that there is no legionella regulation for private rentals, no form to file and no certificate to hold. The duty comes from three places:
- Section 3 of the Health and Safety at Work etc. Act 1974. An employer or self-employed person must conduct their undertaking so that others are not exposed to risks to their health or safety, so far as is reasonably practicable. Letting property is an undertaking, and section 3(2) is the provision the HSE cites for landlords.
- COSHH 2002, regulation 6. A suitable and sufficient assessment of the risk from a hazardous substance, reviewed regularly and at once if there is reason to suspect it is no longer valid.
- The Approved Code of Practice L8 and HSG274 Part 2. L8 (fourth edition, 2013) names landlords as dutyholders, and paragraph 28 covers a building let to tenants where the landlord keeps responsibility for maintenance. HSG274 Part 2 is the technical guidance on hot and cold water systems, first published in 2014 with a second edition in 2024.
An Approved Code of Practice is not law, but if you are prosecuted and did not follow it you must show you complied some other way. So the working standard is L8 and HSG274 Part 2, and the working action is an assessment, a few cheap controls and a written record. The HSE's landlords page says: "Most landlords can assess the risk themselves and do not need to be professionally trained or accredited." The Renters' Rights Act reforms of 1 May 2026 changed the tenancy, not this duty. The gas safety check is annual and the EICR five-yearly, each with its own penalty; legionella has no interval and no fixed fine, which is why the market around it is so confused.
There is no legionella certificate for landlords
Search for "legionella certificate landlord" and you will find annual certificates, testing services and renewal reminders for sale. The HSE landlords page answers each. On the certificate: "Health and safety law does not require landlords to obtain or produce a 'legionella test certificate'." On the interval: "The law does not prescribe that the risk assessment be reviewed on an annual or biennial basis." On testing: sampling "is not usually required for domestic hot and cold water systems". The four myths:
- "You need a new certificate every year." There is no certificate. You need an assessment that is still valid, and it stays valid until something changes.
- "Testing is mandatory." Sampling is for specific situations, such as where temperature control cannot be achieved or a case has been linked to the property.
- "It must be done by an accredited assessor." The law asks for a competent person; for a simple domestic system the HSE says that can be the landlord.
- "Your agent must hold one on file." That is the agent's contract term, not the law, and your own written assessment satisfies it.
Buy a paid assessment because the property needs one, not because a leaflet said the law does.
Legionella risk assessment cost by property type and region
A domestic assessment is a 30 to 60 minute visit: the assessor identifies the system, takes temperatures at the cylinder and at the nearest and furthest taps, checks any tank, photographs showerheads and dead legs, and writes a report with an action list. Price tracks the complexity of the system more than the bedroom count. The ranges below are for the Midlands, the North and the South West; use the certificate cost calculator to adjust for your region and add the gas check, EICR and EPC.
| Property and water system | Risk level | Professional assessment |
|---|---|---|
| Studio or 1-bed flat, combi boiler, mains-fed cold water | Low | £60 to £90 |
| 2 or 3-bed house, combi boiler, no tanks | Low | £60 to £100 |
| 3 or 4-bed house, hot water cylinder and loft tank | Medium | £80 to £120 |
| 5-bed house or small HMO, up to 6 people | Medium to high | £100 to £150 |
| Large HMO, 7 or more people, several bathrooms, stored water | High | £140 to £180 |
Prices include VAT and a written report; tank cleaning, disinfection and pipework are extra. Source: published price lists and cost guides, September 2026.
| Region | Against the base price | 3-bed house with a cylinder |
|---|---|---|
| London | +20 to +30 percent | £100 to £155 |
| South East and East of England | +10 to +15 percent | £90 to £135 |
| Midlands, North West, Yorkshire, South West | Base | £80 to £120 |
| North East | -5 to 0 percent | £75 to £120 |
| Wales | Base | £80 to £120 |
Uplift applied to the base ranges above. A bundled visit with the gas check and EICR is typically 10 to 15 percent cheaper than three bookings. September 2026.
The bottom of each range is a local contractor or a gas engineer adding the assessment to a CP12 visit; the top is a national certificate company or an agent's contractor with a mark-up. Pay for a professional when:
- It is an HMO. More outlets and people, and some councils ask to see an assessment with the HMO licence application or as a licence condition.
- There is stored water or a complex system. A loft tank, a cylinder, long pipe runs, an outbuilding, an unused en-suite or a spa bath.
- Voids are long. A student let over summer, or weeks between tenants.
- Tenants are vulnerable. The HSE lists people over 45, smokers and heavy drinkers, and anyone with chronic respiratory or kidney disease, diabetes, lung or heart disease or an impaired immune system.
What a legionella risk assessment covers
Legionella bacteria multiply between 20 and 45 degrees. The disease is caught by breathing in fine water droplets, not by drinking, so the risk sits where warm water meets a spray: showers, spray taps, spa baths, a connected garden hose. Stagnant water, scale, rust and sludge feed the bacteria. An assessment looks at:
- The water system. Combi or stored cylinder; mains-fed cold water or a loft tank; any outbuilding or outside tap.
- Temperatures. Hot water stored at 60 degrees and 50 degrees at the tap within one minute; cold below 20 degrees within two minutes (HSG274 Part 2, paragraph 2.6 and table 2.1).
- Dead legs and little-used outlets. Capped pipes, the spare bathroom, the utility tap.
- Tanks, showerheads and hoses. Lid, insulation and debris in the tank; scale and biofilm in the showerhead, the classic domestic source.
- Occupancy and tenants. Daily use, voids, and anyone in the higher-risk groups.
- Controls and records. What is done, by whom, and when it is reviewed.
L8's examples of low risk are a small building without people especially at risk, daily water use that turns over the whole system, mains-fed cold water, an instantaneous heater, or no showers. A modern flat with a combi boiler ticks most of those. A Victorian house with a loft tank, a cylinder and an unused bathroom does not.
How to do your own legionella risk assessment
You need a probe thermometer (£10 to £20, the kind sold for cooking), a torch, a phone camera and 30 to 45 minutes, ideally at a change of tenancy.
- Identify the system. Combi or instantaneous heater: no stored hot water. Cylinder: stored hot water, usually with a loft tank.
- Check the cylinder thermostat is at 60 degrees, then run the nearest hot tap: 50 degrees within one minute. Run the furthest hot tap and time it; slow means a long run or a dead leg.
- Run a cold tap for two minutes: below 20 degrees.
- Look in the tank: lid tight, insulated, clean. Photograph it.
- Walk every outlet, note any not used weekly and any capped pipework, and unscrew each showerhead to check for scale.
- Write it up and brief the tenant. The HSE's list: do not turn the thermostat down, clean the showerhead regularly, run every tap after a holiday, report hot water that is not heating.
| Check | What to look for | Pass mark | If it fails |
|---|---|---|---|
| Hot water source | Combi or instantaneous heater, or stored cylinder | Combi: low risk. Cylinder: continue | Note cylinder and tank |
| Cylinder thermostat | Setting on the stat | 60 degrees | Turn it up; add a scald note for tenants |
| Hot tap, nearest and furthest | Temperature after running | 50 degrees within one minute | Check stat, insulation, pipe runs |
| Cold tap | Temperature after two minutes | Below 20 degrees | Insulate tank and pipes |
| Cold water tank | Lid, insulation, debris, vermin | Lidded, insulated, clean, clear water | Fit a lid kit; clean and disinfect |
| Dead legs and unused outlets | Capped pipes, spare bathroom, outside tap, spa bath | None, or flushed weekly | Remove back to the tee, or add to the flushing list |
| Showerheads and hoses | Scale and residue inside | Clean, descaled within 3 months | Descale or replace; brief the tenant |
| Occupancy and tenants | Daily use, voids, anyone in the HSE higher-risk groups | Occupied, all outlets used weekly | Weekly flush during voids; consider a professional if tenants are at risk |
| Record | Date, findings, actions, review trigger, tenant note | Written and filed | Write it up before you leave |
Pass marks from HSG274 Part 2 (paragraphs 2.6 and 2.78, table 2.1) and the HSE landlords page, checked September 2026. Add a column for your answers and the table is your written assessment.
Controls that cost almost nothing
The HSE summary for landlords is "keep the hot water hot, cold water cold and keep it moving". Nearly every control that follows from it is free, which is the strongest argument against buying a certificate and then doing nothing.
| Control | What it does | How often | Typical cost |
|---|---|---|---|
| Cylinder thermostat at 60 degrees | Kills bacteria in stored water | Once, then check each visit | £0 |
| Flush every outlet for several minutes | Clears stagnant water | After any void, weekly during one | £0 |
| Descale showerheads and hoses | Removes the scale bacteria grow in | Every three months | £0 to £5 in descaler |
| Tank lid and insulation | Keeps cold water cold and clean | Once | £20 to £60 |
| Remove dead legs back to the tee | Takes out the stagnant sections | Once | £60 to £150 per leg |
| Thermostatic mixing valve at bath or shower | Stores at 60 degrees without a scald risk | Once | £80 to £150 fitted |
Plumbing prices are typical trade quotes including VAT, September 2026. A combi swap removes stored hot water altogether, but that is a boiler decision, covered in the boiler cover guide.
Two cautions. Water at 50 degrees can scald a small child or a frail adult, which is why HSG274 says the assessment should take account of susceptible people and why a mixing valve, not a lower thermostat, is the answer in a family let. And flushing means running showers, which make the spray you are avoiding: take the head off and run the hose into the tray.
When to review the assessment
There is no statutory interval. COSHH regulation 6(3) requires a review regularly, and immediately if there is reason to suspect the assessment is no longer valid or there has been a significant change. L8 paragraph 47 lists the triggers: changes to the water system or its use, changes to the use of the building, new information, control checks that fail, changes to the people responsible, and a case of Legionnaires' disease linked to the system. Neither names a number of years. A practical rhythm:
- At every change of tenancy. The property is empty and the new tenants may be in a different risk group.
- After any plumbing work. A new bathroom, a boiler swap or a new outside tap all change the system.
- Before and after a void. The HSE says outlets should be used at least once a week, so flush weekly or drain down, then flush every outlet before letting.
- Once a year, alongside the gas check. Not a legal requirement, but a date in the compliance calendar is the only reliable reminder.
Records: L8 paragraph 72 says keep records while current and for at least two years afterwards, and monitoring records for at least five. Strictly that duty falls on employers with five or more employees, and a sole landlord need not record anything. Record it anyway: a dated sheet with photos is the whole of your defence, and a council will ask for it at HMO licensing.
If a tenant contracts Legionnaires' disease and there is no assessment
Legionnaires' disease is notifiable under the Health Protection (Notification) Regulations 2010, so the doctor or laboratory reports the case and the UK Health Security Agency and the council's environmental health team trace where the person was exposed. If the rental is a candidate, its water is sampled: the one situation in which testing genuinely happens, and it is done to you, not by you.
With a written assessment and evidence of the controls you can show you did what was reasonably practicable, the standard section 3 sets. Without one you cannot, and the consequences run three ways:
- Prosecution. A breach of section 3 is an offence under section 33. On conviction on indictment, Schedule 3A provides for an unlimited fine, up to two years in prison, or both. Prosecutions of individual landlords are rare, but the exposure is not capped like the £30,000 EICR penalty.
- A civil claim. A tenant who becomes seriously ill can claim damages for personal injury, and can also use the Homes (Fitness for Human Habitation) Act 2018, which binds every private landlord in England.
- Insurance. Property owners' liability cover would pay a claim, and the insurer's first question is what assessment you had. The landlord insurance guide covers liability cover.
Against that, the assessment is the cheapest document in the file: £0 and half an hour, or £60 to £120 for someone else's. Keep it with the gas record, EICR, EPC and the damp records in the Awaab's Law guide, allow for it in the cost of running a rental, and check the other duties under the Renters' Rights Act with the readiness checker.
Frequently asked questions
How much does a legionella risk assessment cost for a landlord?
£60 to £100 for a flat or house with a combi boiler, £80 to £120 with a cylinder and loft tank, and £100 to £180 for an HMO, outside London. Add 20 to 30 percent in London and 10 to 15 percent in the South East. Doing it yourself costs a £10 to £20 thermometer.
Do landlords legally need a legionella certificate?
No. The HSE states that health and safety law does not require landlords to obtain or produce a legionella test certificate. What it requires, through section 3 of the Health and Safety at Work Act 1974 and COSHH regulation 6, is a risk assessment, and L8 (2013) names landlords as dutyholders.
How often does a landlord need a legionella risk assessment?
There is no fixed interval. COSHH regulation 6(3) requires a review regularly and whenever the assessment may no longer be valid, and the HSE says the law does not prescribe an annual or two-yearly review. Rerun it at each change of tenancy, after plumbing work and after a void of more than a few weeks.
Can I do a legionella risk assessment myself?
Yes. The HSE says most landlords can assess the risk themselves and do not need to be professionally trained or accredited. A simple domestic system takes 30 to 45 minutes with a probe thermometer and the nine-point checklist in this guide, with a dated record kept in the property file.
What temperature should the hot water be to control legionella?
HSG274 Part 2 says hot water should be stored at 60 degrees and reach 50 degrees at the tap within one minute, and cold water should be below 20 degrees within two minutes of running. Legionella multiplies between 20 and 45 degrees, so those settings keep the water outside the growth band.
Does an HMO need a professional legionella risk assessment?
Not by law, but it is where paying £100 to £180 makes most sense: more outlets, more occupants, stored water, and some councils ask to see an assessment with the licence application or as a licence condition. Keep the report with the gas record and EICR in the licence file.
Sources
HSE, Legionella and landlords' responsibilities; HSE, L8 Approved Code of Practice, fourth edition 2013; HSE, HSG274 Part 2, hot and cold water systems; HSE, what Legionnaires' disease is and who is at risk; Health and Safety at Work etc. Act 1974, section 3 and Schedule 3A; COSHH Regulations 2002, regulation 6; Health Protection (Notification) Regulations 2010, Schedule 1; published price lists and cost guides, September 2026. See the methodology.