Who can carry out a legionella risk assessment?
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Key points
- Anyone competent can carry out a legionella risk assessment. There is no licence, no statutory register, and no mandatory qualification.
- Competence means enough training, knowledge, and experience for that system, and it is system-specific: competent for a flat does not mean competent for a hospital.
- The duty holder keeps the responsibility even when they hire an assessor. You can delegate the work, not the duty.
- For simple systems, doing it yourself is expected, not second best.
- Judge an external assessor on method and experience, following L8, HSG274 and BS 8580, not on a certificate alone.
Anyone who is competent can carry out a legionella risk assessment. There is no legal licence for legionella assessors, no statutory register, and no single required qualification. What ACOP L8 requires is that the assessment is suitable and sufficient and carried out by people with enough training, knowledge, and experience to do it properly for the system in front of them. That person might be you, your caretaker, your agent, or a specialist consultant. The right answer depends on the system, not on a job title.
What "competent" actually means
Competence is the word the whole question turns on, and it is more practical than mystical. A competent assessor for a given system can do four things: trace the water system and understand how it behaves; recognise the conditions that let legionella grow, the temperatures, stagnation, dead legs, and nutrient sources covered in what causes legionella; judge realistically who could be exposed and how seriously; and set controls that follow the hierarchy in HSG274, recording all of it in a form that stands up later.
Notice the phrase "for a given system". Competence is specific. A landlord who competently assesses a terraced house with a combi boiler is not thereby competent to assess a hotel with recirculating hot water and a cooling tower, and the law does not pretend otherwise. The question to ask is never "am I allowed to do this" but "do I understand this system well enough to find what is wrong with it".
The duty holder cannot delegate the duty
One point catches people out. Appointing an assessor, even a good one, does not transfer the legal responsibility. The duty holder, the employer, landlord, or person in control of the premises, remains responsible for the assessment being suitable and sufficient and for the controls being carried out. If you appoint someone who is plainly not up to the job, that is your failing, not just theirs. This is why L8 also expects a named responsible person to take day-to-day charge of the scheme: someone has to own it, by name, in writing.
You can delegate the assessment to a competent person. You cannot delegate the duty. Whoever carries it out, the responsibility for it being done properly stays with the duty holder.
Doing it yourself: when that is the right answer
For simple systems, self-assessment is not the budget option; it is what the guidance expects. A house or flat with a combi boiler, a small office with mains-fed water and point-of-use heaters, a single shop unit: these systems are understandable by a conscientious non-specialist with a thermometer and a decent guide. If you can walk the pipework, check the temperatures, spot the little-used outlets, and write down what you found, you are competent for that system. Our page on doing your own assessment sets the boundary in detail, and the free assessment builder structures the work and the record. It guides the recording; the judgement stays with you.
When to hire a specialist
Outside help earns its fee when the system or the exposure outruns you. The clear cases are stored or recirculated hot water serving many outlets, cold water storage tanks feeding a building, cooling towers and evaporative condensers, spa pools, healthcare and care settings where the people exposed are vulnerable, any system you cannot fully trace, and any situation following a positive sample or contact from an enforcing authority. The quieter case is time: an assessment done in a hurry between other jobs is not suitable and sufficient, and paying a competent person is cheaper than a finding later that you never really looked.
Choosing an assessor you can defend
Since there is no register, you choose on evidence. Training in legionella risk assessment and control is the baseline. Experience with systems like yours matters more than the length of the brochure. Ask what standard they assess to: the answer should name L8, HSG274, and BS 8580, the British Standard for legionella risk assessment, and they should be able to describe what the finished assessment will contain and how findings are prioritised before they start. Professional-body membership and accreditation are useful signals, not guarantees. And be wary of the bundled sell: an assessor whose report always concludes you need their company's treatment contract has a conflict worth noticing. What you are buying is an accurate description of your system and a workable scheme of control, not paperwork that certifies the premises safe, because no assessment can do that.
Free legionella risk assessment template
A structured Word document following the five-step approach in ACOP L8. Covers risk identification, written scheme, monitoring, and records. If it isn't written down, you can't evidence it.
Follows ACoP L8 and HSG274 Part 2. Free. No spam.
Free legionella risk assessment template
A structured Word document following the five-step approach in ACOP L8. Covers risk identification, written scheme, monitoring, and records. If it isn't written down, you can't evidence it.
Follows ACoP L8 and HSG274 Part 2. Free. No spam.
Frequently asked questions
Do you need a qualification to do a legionella risk assessment?
No single qualification is required by law. What ACOP L8 requires is competence: enough training, knowledge, and experience to assess the particular system properly. There is no legionella assessor licence and no statutory register. Training courses and professional memberships can evidence competence, but a certificate on the wall is not itself competence, and its absence does not bar you from assessing a simple system you understand.
Who is allowed to do a legionella risk assessment?
Anyone who is competent for the system in question. That may be the duty holder themselves, an employee such as a caretaker or facilities manager, a landlord, a managing agent, or an external water-treatment or hygiene specialist. The law does not restrict who may carry one out; it holds the duty holder responsible for making sure whoever does it is up to the job, because appointing an incompetent assessor is itself a failing.
Can a landlord carry out their own legionella risk assessment?
Yes. The HSE's guidance for landlords says a competent person can carry out the assessment and that, for simple domestic systems, the landlord can be that person. A typical house or flat with a combi boiler or a well-maintained cylinder is within most landlords' reach: identify how water is stored and heated, check temperatures, find little-used outlets and dead legs, set simple controls, and record the lot. Shared or complex systems justify outside help.
What qualifications should a legionella risk assessor have?
Look for evidence of training in legionella control and risk assessment, practical experience with systems like yours, and a method that follows ACOP L8, HSG274, and the BS 8580 standard for risk assessment. Membership of a professional body or accreditation scheme is a useful signal but not proof of quality on its own. Ask what the assessment will contain and how findings are prioritised: a competent assessor can describe that clearly before they start.
When should you hire a professional legionella risk assessor?
Bring in a specialist when the system or the people exposed outrun your own competence: stored or recirculated hot water serving many outlets, cooling towers or evaporative condensers, spa pools, healthcare or care settings with vulnerable people, complex plant you cannot fully trace, or after a positive sample or an enforcement notice. Also hire when you simply lack the time to do it properly, because a rushed self-assessment is not a suitable and sufficient one.
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