Legionella risk assessments in rented property: what the HSE actually expects from agents

Landlords in England must assess the risk of legionella in the water system of every property they let. That duty comes from health and safety law, and the Health and Safety Executive (HSE) says most landlords can do the assessment themselves. There is no legal requirement for a "legionella certificate", and water testing is only needed in specific circumstances.

That matters because agencies are regularly sold annual certificates and sampling they do not need. This guide sets out what the HSE actually expects, what a sensible assessment looks like for an ordinary house or flat, and what to record. Checked against hse.gov.uk on 31 October 2026.

Where the duty comes from

The HSE states that the duty applies to landlords of domestic property, including someone renting out a room in their own home. It is not limited to HMOs or blocks of flats.

What the HSE says is not required

The HSE's landlord page is unusually direct on this point. From the guidance:

• Health and safety law does not require a landlord to obtain or produce a legionella test certificate.
• Landlords do not need professional training or accreditation to assess the risk. Most can do it themselves. If a landlord does not feel competent or does not want to, they can arrange for someone else to do it.
• Sampling for legionella is only needed in very specific circumstances; temperature monitoring is the reliable way to confirm a system is under control.
• There is no set interval for review. The assessment should be reviewed periodically and whenever something changes in the system or how the property is used.
• Landlords are not generally required to record their findings (the statutory record-keeping duty applies to employers with five or more employees), though the HSE says keeping a record is advisable.

An agency that insists on a paid annual certificate from every landlord is therefore asking for something the law does not require. That is a commercial choice, not a compliance one, and should be described as such to landlords.

When a property is low risk

For most domestic properties the risk is low and a simple assessment will show that no further action is needed. The HSE's indicators of a low-risk system are:

• daily water use is enough to turn over the whole system
• cold water comes straight from the mains, with no storage tank
• hot water comes from an instantaneous or low-volume heater, such as a combi boiler, supplying outlets at 50°C or above
• the only outlets are toilets and washbasins

A one-bedroom flat with a combi boiler and a tenant living in it full time ticks every box. A large house with a cold water tank in the loft, a hot water cylinder, several bathrooms and a long void between tenancies does not, and deserves a closer look.

A simple assessment for an ordinary let

The assessment is a short review of the water system and how it is used. For each property, note:

1. Water supply: mains direct, or a cold water storage tank. If a tank, does it have a tight-fitting lid and is it free of debris?
2. Hot water: combi or instantaneous heater, or a stored hot water cylinder. If a cylinder, is it set to store water at 60°C?
3. Outlets: showers, baths, basins, outside taps, and any that are rarely used.
4. Dead legs: redundant pipework left over from removed appliances, which should be removed.
5. Occupancy: full time, part time, or a property that stands empty for weeks.
6. Occupants: anyone at higher risk, such as older or immunosuppressed tenants, which raises the care needed rather than the duty itself.

From that, write down the risk (usually low), the control measures in place, and the date. The HSE's simple control measures are to keep hot water hot, cold water cold and water moving, to flush the system before a new let, to keep tanks clean and lidded, and to remove redundant pipework.

Void periods and tenant advice

Stagnant water is the main domestic risk, and voids are where it happens. The HSE advises using outlets at least once a week to prevent stagnation. For a longer void, either run a flushing regime (run every tap and shower for several minutes, weekly) or drain the system. For an agency, that means a dated void checklist entry each week, and a full flush before the new tenant moves in.

Once the tenant is in, the HSE suggests landlords give them simple advice:

• do not adjust the hot water cylinder temperature
• clean and descale showerheads regularly
• report any problem with the hot water, or any fault with the water system, to the landlord or agent

Putting these three lines in the move-in pack covers it. Our guide to the written information agents must give tenants covers the statutory documents the pack also needs.

Reviewing the assessment, and what happens if it goes wrong

Because there is no fixed interval, agencies tend to pick a review cycle and apply it consistently. Common practice is to review at each change of tenancy and after any change to the water system, such as a new boiler, a removed bath or a new tank. Where access to an occupied property is difficult, the HSE notes that checks can be made during other visits, such as the annual gas safety check or a routine inspection. See our guide to gas safety certificates.

The HSE and local authorities do not proactively inspect domestic premises or ask to see legionella assessments. The risk is after the event: if a tenant contracts Legionnaires' disease from the property's water system, the landlord may be prosecuted under the Health and Safety at Work Act and would need to show they had met their duty. A short dated assessment, with the control measures and the void flushing records, is the evidence that does that.

Checklist for agencies

1. Add legionella to the compliance record of every managed property, as a recommended item rather than a certificate.
2. Complete a simple written assessment per property, with the date and who did it.
3. Set the hot water cylinder to 60°C where there is one, and record it.
4. Flush every outlet before each new tenancy and log weekly flushing during voids.
5. Put the three tenant advice points in the move-in pack.
6. Review at each change of tenancy and after any plumbing change.
7. Only commission a specialist or sampling where the system is complex or the simple assessment points to a real risk.

How Letfold helps

Letfold lists a legionella risk assessment as a recommended compliance item on each property, separate from the legally required certificates, with a review date and reminders before it falls due. The assessment document is stored against the property, and a repair raised by a tenant about hot water or the water system sits on the same record. See compliance tracking and the compliance checklist.

Frequently asked questions

Is a legionella risk assessment a legal requirement for landlords?

Yes. Landlords must assess the risk of legionella under the Health and Safety at Work Act and COSHH. For most homes the assessment is simple and shows a low risk.

Do landlords 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.

Who can carry out the assessment?

The landlord, or the agent on their behalf, can do it. The HSE says no professional training or accreditation is needed, provided the person is competent for a simple domestic system.

How often should a legionella assessment be reviewed?

The law sets no interval. Review it periodically and whenever the water system or the way the property is used changes. Many agencies review at each change of tenancy.

Does the water need to be tested?

Not usually. Sampling is only needed in specific circumstances. Temperature checks are the normal way to confirm the system is under control.

Sources

Checked on 31 October 2026:

• Legionella and landlords' responsibilities (hse.gov.uk)
• Legionnaires' disease: the control of legionella bacteria in water systems (L8) (hse.gov.uk)

This article is general information for England, not legal advice.