If you rent out property, sooner or later you will get the call or the email: your property is legally required to have a legionella test, and for a fee, they can supply the certificate.
It is not true. The Health and Safety Executive, which enforces this area of law, says so directly: "Health and safety law does not require landlords to obtain or produce a legionella test certificate."
There is a real duty here. It is just not the one being sold to you. Here is what the law actually asks for.
What the law does require
Landlords have a duty under the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health Regulations to assess and control the risk of exposure to legionella bacteria in the water system of a property they let.
In practice that means one thing: a risk assessment. Not a test, not a certificate, and not, in the vast majority of cases, a specialist contractor.
Who can carry out the assessment
You can, in most cases. The HSE's position is that "most landlords can assess the risk themselves and do not need to be professionally trained or accredited". If you do not feel competent to do it, you can arrange for someone else to do it on your behalf, but that is a choice, not a legal requirement.
This is the point at which a lot of money changes hands unnecessarily. A single-let flat with a combi boiler and no stored hot water is close to the lowest-risk water system there is.
What the assessment looks at
Legionella bacteria multiply in water held between roughly 20°C and 45°C, and cause harm when that water is breathed in as a fine spray, typically from a shower. A domestic assessment is essentially a walk through the water system asking where those conditions could arise:
- Is there a cold water storage tank, or a hot water cylinder, rather than a combi boiler heating on demand
- Is hot water stored at 60°C and delivered to the outlets at 50°C or above
- Is cold water staying below 20°C
- Are there any dead legs, lengths of redundant pipework where water sits still
- Are there outlets that go unused for long periods, an ensuite in a spare room, an outside tap
- Is there debris, rust, or sludge in a tank, and is the tank lid intact
- Are there showers, spa baths, or anything else that creates a spray
The controls that follow are equally ordinary: keep hot water hot and cold water cold, remove dead legs when you next have a plumber in, clean shower heads periodically, and tell tenants to run taps and showers for a few minutes if the property has been empty.
The instruction that matters most is the one you give the tenant
The highest-risk moment in a domestic property is a void period, or a tenant returning from a long absence, when water has been sitting in the pipes. A line in the tenancy pack asking the tenant to run all outlets for a few minutes after any period of a week or more without use costs nothing and addresses the main practical risk.
Keep a note that you gave that instruction. Along with the assessment itself, it is what demonstrates you took the duty seriously.
How often should it be reviewed?
There is no legal answer, and anyone quoting you one is guessing. The HSE states that "the law does not prescribe that the risk assessment be reviewed on an annual or biennial basis", only that it should be reviewed periodically in case anything changes.
What counts as a change: new tenants, a new boiler or cylinder, a bathroom refit, a long void, or any work on the pipework. Many landlords settle on a two-year review as a practical rhythm and bring it forward when one of those happens. That is a sensible habit, not a legal deadline, and it is worth being clear about the difference.
How to tell a real service from a scare
Some properties genuinely benefit from professional help: large HMOs, blocks with communal tanks, anything with a complex or stored-water system. The warning signs of the other kind of offer are consistent:
- It claims a certificate is a legal requirement. It is not
- It claims annual testing is a legal requirement. It is not
- It quotes a fine for not having a certificate. There is no such offence
- It arrives cold, by phone or email, referencing your property address
The duty is real, the enforcement is real, and a landlord who has never thought about legionella at all is exposed. But what closes that exposure is a written assessment and a handful of sensible controls, not a purchased document.
Where this sits alongside everything else
Legionella is one of a small number of landlord obligations with no certificate attached, which is exactly why it gets forgotten. The UK landlord compliance checklist puts it next to the ones that do produce documents, and the penalties guide covers what actually happens when each obligation is missed.
If you want to know which of yours are currently unmet, the compliance quiz takes about a minute.
Written by The PropCert team
PropCert builds certificate tracking for UK landlords. Every guide is checked against the primary source, gov.uk, HSE, or the legislation itself.
This guide is general information about landlord obligations in England, not legal advice. Where a decision turns on your specific circumstances, check the primary source or take advice.