Short answer: no. Health and safety law does not require a landlord to obtain or produce a “legionella test certificate”. There is no such document in law, no body that issues one, and no standard it would be issued against.

The Health and Safety Executive says this in plain terms on its own page for landlords. It is worth knowing, because “you need a legionella certificate before you can let this property” is a sentence a lot of landlords have been told, usually by someone selling one.

Where the myth comes from

Two true things get welded into one false one.

True: landlords do have a legal duty about legionella. It comes from general health and safety law, expanded in the Approved Code of Practice L8 and the technical guidance HSG274.

True: for some water systems, particularly large, complex, communal or healthcare ones, a serious monitoring regime is appropriate and specialists are worth paying.

False: that this produces a certificate, and that every rented property needs one before letting.

The gap between the duty and the paperwork is where a small industry has grown up. The duty is to do something. A certificate is a receipt for having paid someone.

What the law actually asks for

Four things, in this order:

  1. Assess the risk in the property’s water system.
  2. Control what the assessment finds, proportionately.
  3. Review the assessment when there is reason to think it is no longer valid.
  4. Be able to show what you did.

For most domestic systems, HSE describes the risk as generally low: small domestic-type systems, in regular use, with water turning over frequently. The control measures that follow are correspondingly simple. HSE’s own suggestions for these systems include flushing the system before letting, keeping debris out of it, keeping hot water at the right temperature, removing redundant pipework, and asking tenants to clean showerheads regularly. Cold water fed directly from the mains, with no storage tank, removes a whole category of risk on its own.

None of that produces a certificate. All of it is the actual job.

Why sampling is usually the wrong tool

Testing for legionella means taking water samples and culturing them, which takes days and tells you about the water in that outlet on that morning. HSE says testing is not usually required for domestic hot and cold water systems and is only needed in very specific circumstances.

The reason is that sampling is a snapshot, not a control. What manages the risk is keeping hot water hot, keeping cold water cold, and not letting water sit still. A clear sample from a system with no controls is luck; a well-controlled system does not need one to prove it is well controlled.

If someone proposes routine sampling for an ordinary flat, ask them which specific circumstance in the guidance they think applies.

Do you need to keep records?

Here is a nuance worth having straight. The Approved Code of Practice L8 says monitoring records should be kept for at least five years (paragraph 72), and asks for records to be signed or otherwise authenticated (paragraph 73). But HSE’s landlord guidance points out that the statutory duty to keep records applies to employers with five or more employees. Many private landlords are below that line and are not legally required to record anything.

Keep records anyway. Not because a form demands it, but because “I assessed the risk and controlled it” is a claim, and a dated log of what was checked and when is the only thing that turns it into evidence. If a tenant becomes unwell, or an insurer or an environmental health officer asks, the difference between a record and a recollection is total.

What to say when someone sells you one

You do not have to be combative about it. Three questions do the work:

  1. “What is the certificate certifying against?” There is no standard for a legionella certificate for a domestic let, so there is no honest answer.
  2. “Are you offering a risk assessment?” If they are, that is a real and sometimes useful service. Ask what it will cover and who is doing it.
  3. “Which specific circumstance makes sampling necessary here?” For a simple system in regular use, there usually is not one.

A reputable water hygiene company will answer all three straightforwardly. Plenty do this work well, and complex systems genuinely need them.

What to do instead, this week

  • Walk the system. Where is the hot water made and stored? Is there a cold tank, or is the cold straight off the main? Are there outlets nobody uses?
  • Write down what you found and what you are doing about it. It does not need to be long.
  • Fix the obvious: remove dead legs, set the cylinder correctly, flush anything that sits unused, and flush the whole system between tenancies.
  • If the system has stored hot water, circulation or a tank, look at whether temperature monitoring is proportionate. What the checks actually mean covers the regime, and what temperature hot water should be covers the numbers.
  • Keep the record. That is what Legionella Logger is for: the schedule, the timed readings, the pass or fail, and a PDF log you can hand over. It records a monitoring regime. It is not a risk assessment and it is not a certificate, because neither of those is a thing a phone app can honestly issue.

Sources

HSE: legionella and landlords’ responsibilities, the Approved Code of Practice L8, and the technical guidance HSG274. All free to read.

Statements about HSE guidance were checked against hse.gov.uk on 10 September 2026; L8 and HSG274 references against the archived HSE PDFs. Contains public sector information licensed under the Open Government Licence v3.0. This is general information about published guidance, not a legionella risk assessment and not legal advice. Plan CD is not affiliated with the Health and Safety Executive.