Great Britain only
This guide follows guidance from the Health and Safety Executive (HSE), which covers England, Scotland and Wales. Northern Ireland has its own regulator and is not covered. It is general information, not a risk assessment of your property.
The short version
- Yes, landlords have a duty. If you let a home under a lease or licence of less than seven years, you must make sure the risk of legionella to your tenants is properly assessed and controlled. HSE bases this on section 3 of the Health and Safety at Work etc Act 1974 and the Control of Substances Hazardous to Health Regulations 2002 (COSHH).
- The assessment can be simple. HSE says the law does not require an in-depth, detailed assessment. Most landlords can do it themselves if they are competent, or ask someone who is.
- You do not need a “legionella certificate”. HSE says health and safety law does not require a legionella test certificate, and routine water testing is not usually needed for domestic systems.
- Writing it down is not strictly required for landlords, but HSE suggests keeping a record anyway. That duty to record applies to employers with five or more employees.
- Keep water moving, hot hot and cold cold. Temperature control is the most reliable way to keep the risk down.
What legionella is, in one paragraph
Legionella bacteria live in water. They can multiply in warm, stagnant water and cause Legionnaires’ disease when people breathe in tiny droplets, for example from a shower. The risk in a normal home is usually low, which is why HSE asks for a proportionate response and not a laboratory programme.
Does your property look low risk?
HSE gives an example of a low-risk, simple system. All of these apply:
- it is a small building with a domestic-type water system
- the whole system is used every day, so the water turns over
- cold water comes straight from the mains, with no storage tank
- hot water comes from an instantaneous or low-volume heater, supplying outlets at 50°C
- the only outlets are toilets and wash hand basins
A simple assessment of a system like this may find no real risk, but you should review it if the system changes. Instantaneous heaters such as combi boilers and electric showers lower the risk because they do not store water.
Most real homes have a shower, and some have a stored hot water cylinder or a loft tank. Those are the things to look at first.
| Check this | Why it matters | Simple control |
|---|---|---|
| Hot water cylinder | Stored warm water is where bacteria can grow | Set the thermostat so the water is stored at 60°C |
| Cold water tank in the loft | Water can sit and warm up | Tight-fitting lid, and keep debris out |
| Shower | Showers make a fine spray that can be breathed in | Tenants clean and disinfect the head regularly |
| Taps or showers that are rarely used | Stagnant water | Run them, or remove the unused pipework |
| Empty property | Water stands still | Flush before letting, and use every outlet at least once a week while empty |
| Old pipework left in place | Water stands in unused pipe | Remove redundant pipework |
The temperature figures
HSE’s technical guidance for hot and cold water systems (HSG274 Part 2, 2024) gives these targets.
| Part of the system | Target |
|---|---|
| Hot water stored | At least 60°C |
| Hot water at the outlets | 50°C within one minute of running the tap |
| Cold water | Below 20°C within two minutes of running the cold tap |
The monitoring tables in the same guidance, which are written for all kinds of water system, list monthly temperature checks at sentinel taps (those nearest to and furthest from the tank or cylinder) and quarterly cleaning of showerheads and hoses. HSE asks landlords for a proportionate approach, so a small house with a simple system does not need that full programme, but the numbers show what a good check looks like. HSE says temperature monitoring is a reliable way to confirm a domestic system is under control.
Empty properties and changeovers
The risk goes up when a home is empty, because the water stops moving. HSG274 says that as a general principle outlets on both hot and cold systems should be used at least once a week. For a home that will stay empty for a long time, consider a flushing routine or draining the system.
At the start of a new tenancy, flush the system before letting, as close to the move-in date as you can. Between tenants, a short checklist is enough. This one is our suggestion, built from the HSE measures above:
- Run every tap and shower for a few minutes before the new tenant arrives.
- Check the cylinder thermostat is at 60°C and that the hot tap reaches 50°C within a minute.
- Check the loft tank, if there is one, for a tight lid and for debris.
- Look for pipework that goes nowhere and have it removed.
- Clean and disinfect the showerhead and hose.
What to tell your tenants
HSG274 says landlords should tell tenants about the risk and what the assessment found. HSE suggests tenants should:
- not alter the cylinder temperature setting
- clean and disinfect their showerhead regularly
- tell you if the hot water is not heating properly or anything else is wrong
A one-page note at the start of the tenancy, with the date you gave it, covers this.
Reviewing and checking
The law does not say how often to review. HSE says to review the assessment periodically in case anything changes in the system, and when it does, for example a new boiler, a new shower or an extension. If it is hard to get into an occupied home, HSG274 says checks can be made during visits you already make, such as gas safety checks or routine maintenance.
If you use a letting agent, the management contract should say clearly who is responsible for legionella. Where it does not, the duty falls on whoever controls the premises and the water system, which in most cases is the landlord.
A record worth keeping
You are not generally required to write it down, but if a tenant ever became ill you would need to show you had met your duty. HSE says inspectors do not proactively inspect homes or ask for evidence, but a landlord can be prosecuted if a tenant catches Legionnaires’ disease from the water system. A one-page record per property makes that easy:
| Item | What to write |
|---|---|
| Property and date of assessment | Address, date, who did it |
| System type | Combi boiler, cylinder, tank, electric shower |
| Risk findings | Low risk, or the things you found |
| Actions taken | Thermostat set, lid fitted, pipework removed |
| Tenant note | Date given |
| Between-tenancy checks | Date, flush done, shower cleaned |
| Review date | Next time, or the date something changed |
When to get help
Use someone competent if the property has a tank and cylinder you cannot check yourself, several flats sharing one system, communal showers, or if you are not confident about your own assessment. HSE’s technical guidance also notes that it can be impractical to assess every unit in a large portfolio, and suggests a representative sample on a rolling programme.
Frequently asked questions
Do I need a legionella risk assessment for a rented house?
Yes, in the sense that you must assess and control the risk. HSE says this does not need to be in-depth, and most landlords can do it themselves if competent. For a simple system the assessment may show there is no real risk.
Do I need a legionella certificate or a water test?
HSE says the law does not require a legionella test certificate, and routine testing is not usually needed for domestic systems. Temperature monitoring is its suggested way of showing control.
How often should I review it?
There is no fixed period in law. Review it periodically and whenever the water system changes.
Does a holiday let have different rules?
Short lets can bring extra conditions, for example from your council or licensing scheme. Check yours. The HSE duty applies to landlords letting under a lease or licence of under seven years.
Sources
Last checked 22 October 2026.
- Legionella and landlords’ responsibilities, HSE
- Legionnaires’ disease: Technical guidance, Part 2: the control of legionella bacteria in hot and cold water systems (HSG274 Part 2, 2024), HSE, paragraphs 2.138 to 2.146 and the monitoring tables
- Legionnaires’ disease: what you must do, HSE
Changes to this guide
- 22 October 2026: Published.
This guide is general information written from the official sources listed above and checked on 22 October 2026. It is not legal, tax or financial advice, and Plainfiles is not endorsed by any government body. Rules change, so check the linked official pages for your own situation. Written and designed by Plainfiles with the help of artificial intelligence (AI) tools, then checked against the official legislation and guidance listed in the sources. How we write and check our guides.