Quick answer: There is no such thing as a legally required "legionella certificate" for a residential landlord. The Health and Safety Executive says so directly: "Health and safety law does not require landlords to obtain or produce a 'legionella test certificate'." What the law does require is a risk assessment, under the Health and Safety at Work etc. Act 1974 and COSHH 2002, with ACoP L8 as the approved code of practice. And HSE states that "most landlords can assess the risk themselves and do not need to be professionally trained or accredited." There's also no legal requirement to review it annually. HSE: "The law does not prescribe that the risk assessment be reviewed on an annual or biennial basis."
We sell legionella risk assessments. We're about to explain why most landlords of a standard flat probably don't need to buy one from us.
That's an odd way to run a business page. But this is the single most mis-sold service in UK lettings, and landlords get scare letters about it constantly, so somebody in the industry should just say what the law is.
The three things people confuse
| Legionella risk assessment | Legionella test (sampling) | "Legionella certificate" | |
|---|---|---|---|
| What it is | An assessment of whether your water system could allow legionella bacteria to grow, and what controls are needed | A physical water sample sent to a lab to detect bacteria | A document some contractors issue after a visit |
| Legally required? | Yes, as part of your general duty under HSWA 1974 and COSHH 2002 | No, not routinely for domestic lets | No such legal requirement exists |
| Who can do it | Most landlords, themselves. No training or accreditation required per HSE | A laboratory, via a sampling contractor | n/a |
| How often | Reviewed when something changes. No fixed statutory interval | Only where the assessment identifies a specific need | n/a |
| Typical London cost | £0 if self-assessed, or £79 to £299 if outsourced | £50 to £150+ per sample | Whatever the contractor charges |
What the HSE actually says
This is worth quoting properly, because contractor letters often paraphrase it into something quite different.
Direct from HSE guidance for landlords:
"Health and safety law does not require landlords to obtain or produce a 'legionella test certificate'."
"Most landlords can assess the risk themselves and do not need to be professionally trained or accredited. However, if they do not feel competent, or inclined to do so, they can arrange for someone to do it on their behalf."
"The law does not prescribe that the risk assessment be reviewed on an annual or biennial basis. It is important to review the assessment periodically in case anything changes."
Source: HSE, Legionella and landlords' responsibilities
So where does the legal duty come from?
Three places, none of which mentions a certificate.
- Health and Safety at Work etc. Act 1974. Section 3 places a duty on those in control of premises to ensure, so far as reasonably practicable, that people not in their employment aren't exposed to health and safety risks. Letting a property brings you within that.
- Control of Substances Hazardous to Health Regulations 2002 (COSHH). Legionella bacteria are a biological agent, so the duty to assess and control the risk applies.
- ACoP L8 and HSG274. The approved code of practice and technical guidance on controlling legionella. These describe how to control the risk, not how to certify it.
The duty is to assess and control. Not to test. Not to certify. And not on a calendar.
What a defensible self-assessment actually needs to record
If you do it yourself, and for most standard domestic lets you can, this is roughly what it should cover. Write it down, date it, keep it.
- The property and water system. Address, type of system (combi boiler, hot water cylinder, cold water storage tank), and whether there's any stored water.
- Where water could stagnate. Rarely used outlets, long dead legs of pipework, an unused en-suite, an outside tap.
- Temperatures. Hot water should be stored above 60°C and reach the tap at 50°C or above within a minute. Cold water should stay below 20°C.
- Who uses the property. Higher risk if occupants are elderly, immunosuppressed, or have respiratory conditions.
- Any showers. Showers create aerosols, which is the main transmission route. Note the shower head condition and descaling.
- Controls you've put in place. Flushing regime for voids and rarely used outlets, descaling shower heads, temperature checks.
- Tenant advice given. Written guidance to run taps and showers after any period of absence.
- Review trigger. Note what would prompt a review: a new water system, works to the pipework, a change in occupancy, a void period.
The bit HSE emphasises that contractors rarely mention: HSE draws a clear distinction between testing and temperature monitoring, describing monitoring as "a reliable method for confirming the water system is under control." For a standard flat, a thermometer and a written record does more for compliance than a lab sample does.
When a paid assessment genuinely is worth it
This isn't a case of "never buy one". There are situations where a professional assessment is the right call, and where we'd tell you to book it.
- Stored water. A cold water storage tank or a hot water cylinder changes the risk profile substantially compared with a combi.
- Larger HMOs. More outlets, more variable occupancy, more void rooms, more stagnation risk.
- Commercial premises. The duty is heavier and the systems are usually more complex.
- Vulnerable occupants. Sheltered accommodation, or where you know occupants are immunosuppressed or elderly.
- Spa baths, hot tubs, or unusual systems. Higher risk and outside most landlords' competence to assess.
- You simply don't want to. HSE explicitly allows you to appoint someone. That's a legitimate choice, not a legal necessity.
How to respond to a scare letter
Landlords regularly receive letters, sometimes from managing agents, styled to look official and quoting large fines for not holding a "legionella certificate".
If you get one:
- Check it against the HSE page linked above. Not against the contractor's own website.
- Ask which specific regulation requires a certificate. There isn't one, so there won't be a clean answer.
- Ask whether the sender profits from the service they're recommending. Often the assessment provider also quotes for the remedial work.
- Do the assessment anyway. The assessment duty is real. Just don't buy a certificate that doesn't legally exist.
If your managing agent insists as a condition of a block policy or a lease, that's a contractual matter rather than a legal one. Different question, and worth arguing separately.
Sources
- HSE: Legionella and landlords' responsibilities
- Health and Safety at Work etc. Act 1974, s.3
- Control of Substances Hazardous to Health Regulations 2002
- HSE ACoP L8, Legionnaires' disease: The control of legionella bacteria in water systems, and HSG274 Part 2 (hot and cold water systems)
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About the author
My Landlord Certificate Compliance Team
This guide was written and fact-checked by the My Landlord Certificate compliance team and reviewed against current UK legislation by our NICEIC-approved, NAPIT-registered, Gas Safe registered, accredited DEA and NEBOSH-qualified engineers. We help landlords across all 33 London boroughs stay compliant with fixed-price EICR, Gas Safety (CP12), EPC, Fire Risk Assessment and PAT testing.