Landlords in Great Britain must assess the risk from legionella in the water systems of the homes they let. HSE says that for a typical house or flat the assessment can be simple, most landlords can do it themselves, no certificate is needed and routine water testing is not usually required. This page is the overview; the guides linked below go into detail.
Legionella is the bacterium that causes Legionnaires’ disease, which HSE describes as a potentially fatal form of pneumonia. People catch it by breathing in tiny droplets of water that contain the bacteria, and 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, and when it contains deposits such as scale or rust. That is why showers, stored hot water, unused taps and empty properties are the things to look at in a rented home.
What does the law require of landlords?
The duty comes from the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health Regulations (COSHH). HSE treats a landlord as anyone who rents out a property they own under a lease or licence shorter than seven years, including councils, housing associations and people letting a room in their own home. Landlords are treated as self-employed under the Act and owe a duty of care to their tenants.
HSE adds that the risks from hot and cold water systems in most residential settings are generally considered to be low, and that the risk is lowest where water is used daily, cold water comes direct from the mains and hot water comes from instantaneous or low-volume heaters. Our full guide, legionella risk assessment for landlords, sets out the checklist.
Who has to do the risk assessment, and who can?
The landlord is responsible. 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. If an agent manages the property, agree in writing what they check and record.
In our view a professional makes sense where the system is not simple: a shared house or HMO with several bathrooms, stored hot water or cold water tanks you cannot easily check, rarely used showers, long or frequent void periods, or shared plumbing in a block. These are our judgement, not HSE rules.
How often must a legionella risk assessment be reviewed?
In England and Wales the law sets no fixed interval. HSE says the law does not prescribe annual or two-yearly review; you review the assessment periodically and whenever something changes, such as a new boiler, cylinder or bathroom, a long void or a hot water complaint. Scotland is stricter: the Repairing Standard statutory guidance says all water systems must be assessed before the property is first let and the assessment should be reviewed at intervals of no more than two years. You can use the renewal calendar to keep track of dates.
What do landlords have to do in practice?
HSE’s advice for most domestic systems comes down to temperature control and use. In summary:
- keep the hot water hot: set the cylinder so water is stored at 60°C, with low-volume heaters supplying outlets at 50°C
- keep cold water cold: below 20°C where possible, with any cold water tank covered by a tight-fitting lid
- keep water moving: remove redundant pipework and dead ends, and use every outlet at least weekly in a vacant property
- flush the system before a new let, and flush or drain for a long vacancy
- tell tenants not to change the cylinder setting, to clean and disinfect showerheads regularly, and to report hot water that is not heating properly
- write a short dated note of what you found and did, and set a review date
HSE says recording the assessment is a statutory duty only for employers with five or more employees, but keeping a record is advisable, and we would. Landlords should also note the scalding risk: HSE flags water above 44°C at baths and showers, so temperature control and scald protection go together.
Do landlords need a legionella certificate or water test?
No. HSE says landlords are not required to obtain or produce a legionella test certificate, and routine testing is not usually required for domestic systems. 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 the recommended temperatures are not consistently met. If you test, HSE says samples should go to a UKAS-accredited laboratory and sampling should follow BS 7592.
What does a legionella risk assessment cost?
The prices below come from published cost guides and provider pages we found in October 2026, not from our own survey. They are a guide to the range, not an offer.
| Item | Published price |
|---|---|
| Self-assessment following HSE guidance | Free; a guided online template was listed at £12.95 |
| Professional assessment, one or two bed flat | £70 to £120 plus VAT |
| Professional assessment, three or four bed house with a cylinder | £90 to £200 plus VAT |
| HMO or shared house | £250 to £450 plus VAT |
| Single laboratory sample, if testing is needed | About £83 plus VAT, falling with volume |
The figures, sources and the questions to ask before accepting a quote are in our guide to legionella risk assessment cost. If you want to compare local assessors, use the quote form below or our find a professional page.
What are the penalties and how is the duty enforced?
HSE and local authority inspectors do not proactively inspect domestic premises or ask for evidence of risk assessments. The risk arises after the event: 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 duty. Schedule 3A to the Act sets the penalties for failing to discharge the duties in sections 2 to 6 or for breaching health and safety regulations: on summary conviction up to 12 months’ imprisonment, a fine not exceeding £20,000, or both, and on indictment up to two years’ imprisonment, a fine, or both. A dated record of what you did is the practical protection.
Legionella rules in England, Wales, Scotland and Northern Ireland
| Nation | Position |
|---|---|
| England and Wales | HSE’s guidance for landlords applies across Great Britain: assess the risk, light-touch for a typical home, no certificate required, review if the system changes |
| Scotland | The Repairing Standard statutory guidance for private landlords says to assess the hot and cold water systems before the first let, review at least every two years, flush before letting if not done in the previous two years, store hot water at 60°C or above, remove redundant pipework and dead ends, advise tenants of the control measures and prevent stagnation in vacant property |
| Northern Ireland | The Health and Safety at Work (Northern Ireland) Order 1978 and COSHH (Northern Ireland) 2003 apply, and HSENI points to L8 for practical guidance. We did not find guidance written for domestic landlords there; check with HSENI or your council |
Guides in this section
- Legionella risk assessment for landlords: what the law requires, the do-it-yourself checklist and when to pay a professional.
- Legionella risk assessment cost: published prices by property type, lab testing costs and how often to review.
- Landlord certificates checklist: the gas, electrical and other checks that do come with certificates.
- Compliance checker: see which obligations apply to your property.
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 have to do a legionella risk assessment?
Yes. HSE says landlords have a duty to assess the risk from legionella in the water systems of rented homes, but a detailed assessment is not required for a typical domestic property. A simple assessment may find that no further action is needed. It should be reviewed if the water system changes.
Can I do my 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 inclination, you can arrange for someone else to do it. A professional is more sensible for HMOs, stored hot water, rarely used showers or long voids.
Do I need a legionella certificate for my rental 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 a review when things change.
How often should a landlord review a legionella risk assessment?
England and Wales have no fixed interval; HSE says only that you review it periodically and when something changes. Scottish Repairing Standard guidance says to assess before the first let and review at intervals of no more than two years. Review sooner after a new boiler, cylinder or bathroom, or a long void.
How much does a legionella risk assessment cost?
Published prices we found in October 2026 were about £70 to £200 plus VAT for a typical flat or house, and £250 to £450 plus VAT for an HMO or shared house. Doing it yourself is free. These come from cost guides and provider pages, not our own survey.
Sources, checked on 30 October 2026
- HSE: Legionella and landlords' responsibilities
- HSE: Legionnaires' disease. The control of legionella bacteria in water systems (L8)
- HSE: What is Legionnaires' disease?
- HSE: Hot and cold water systems
- HSE: Testing and monitoring your water system for legionella
- legislation.gov.uk: Health and Safety at Work etc. Act 1974, Schedule 3A
- Scottish Government: Repairing Standard statutory guidance for private landlords, Annex D1
- HSENI: Legionella