Duty holder, responsible person, competent person: who is who?
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Key points
- The duty holder holds the legal duty and cannot give it away: usually the employer, landlord or person in control of the premises.
- The responsible person is appointed by the duty holder to manage the control scheme day to day. The appointment shares the workload, never the liability.
- The competent person is not a third job but a standard: anyone doing a legionella task must have the knowledge, training and experience to do it properly.
- One individual can hold all three positions; in a small business or single let, that is normal. In a large organisation they are usually split across several people.
- Most enforcement cases trace back to nobody clearly holding each role: the letters, appointments and scope were never written down.
Three terms run through every page of legionella guidance, and they are not interchangeable. The duty holder is who the law holds accountable. The responsible person is who manages the risk day to day. The competent person is a standard anyone doing the work must meet. Getting the three straight decides who is answerable when something goes wrong.
The duty holder: where the law lands
The duty holder is whoever holds the legal duty because they control the premises or run the undertaking. The duty itself comes from the Health and Safety at Work etc. Act 1974, reinforced by the COSHH Regulations and explained in ACOP L8. In a workplace it is the employer. In a rented property it is the landlord or whoever controls the building's water system. Where control is split, for example a freeholder and a managing agent sharing a block, each can be a duty holder for what they control.
The defining feature of the role is that it cannot be delegated. The duty holder can appoint people, hire contractors and buy services, but none of that moves the accountability. When the HSE brings a case, it is the duty holder who sits in the dock.
The responsible person: who does the work
ACOP L8 expects the duty holder to appoint a competent individual to take day-to-day charge of controlling the risk: the responsible person. They keep the risk assessment current, make sure the written scheme of control is followed, oversee the monitoring, and act when a reading falls out of range. The role, and what competence means for it, is covered in full on the responsible person page, and the appointment itself should be recorded in writing using an appointment letter.
The responsible person answers to the duty holder; the duty holder answers to the law. Both statements are true at once, and the second one never changes.
The competent person: a standard, not a job title
"Competent person" causes the most confusion of the three, because it sounds like a position to fill. It is better read as a test applied to whoever does each task. The Management of Health and Safety at Work Regulations require the duty holder to appoint competent assistance for health and safety, and ACOP L8 applies the same idea to legionella: anyone assessing, sampling, servicing or monitoring must have the knowledge, training and experience to do that task properly.
So the competent person might be the responsible person (competent to manage the scheme), an external assessor (competent to survey a complex system), or a plumber (competent to service a TMV). One person can be competent at several tasks; nobody has to be competent at all of them. The duty holder's job is to check competence matches the task and to keep a record of it.
Who holds which role: five common setups
| Premises | Duty holder | Responsible person | Where competence usually comes from |
|---|---|---|---|
| Small office, owner-managed | The employer (company or owner) | Often the same person, or the office manager | Short responsible-person course; simple system |
| Single residential let | The landlord | Usually the landlord | Self-assessment of a simple system, using a structured assessment |
| HMO or block with shared systems | Landlord, freeholder or managing agent, per the lease | The agent's property manager, formally appointed | Trained in-house manager plus contractor support |
| Care home group | The provider organisation | A named estates or facilities manager per home | Formal training, specialist contractor, healthcare guidance |
| School | The local authority, academy trust or governing body | The site manager or business manager | Site-staff training plus competent contractor for plant |
Notice the pattern in the first two rows: one person holding every role is normal and acceptable where the system is simple. The mistakes begin when the organisation grows but the paperwork does not, and nobody can say who holds which role any more.
Ask three questions of any building: who is accountable in law, who manages it daily, and is each person doing a task competent for that task? If any answer is "we assume someone", that is the gap to close first.
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.
The three assumptions that blur the roles
"The contractor handles it." Hiring a water treatment company makes the contractor a competent person for the tasks they perform. It does not make them the duty holder, and unless they are formally appointed it does not make them the responsible person either. Someone in-house still has to manage the relationship and hold the records.
"The tenant uses the water." A tenant's use of a system does not move the duty. Landlords keep it for the property they let; in commercial premises the split follows who controls which part of the system, which the lease should spell out.
"The caretaker just does the checks." The person running the taps may be competent for the checks but is not automatically the responsible person, and is certainly not the duty holder. If the organisation has never said who is appointed, the honest answer is that nobody is, and that is exactly what an inspector's first questions will expose.
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
Who is the duty holder for legionella?
The duty holder is whoever carries the legal duty for the premises: the employer in a workplace, the landlord or person in control of a rented property, and the owner or managing agent of a building with shared water systems. The duty comes from the Health and Safety at Work etc. Act 1974 and the COSHH Regulations, and it cannot be delegated away, though the day-to-day work can be shared with an appointed responsible person.
Can the duty holder and the responsible person be the same person?
Yes, and in small organisations they usually are. A sole trader, a landlord with one flat, or the owner-manager of a small business often holds both roles at once. What matters is that both jobs are done: the accountability is accepted and the day-to-day management happens. Writing the appointment down is still worthwhile, because it names a deputy and shows the arrangement was deliberate.
Is a managing agent the duty holder?
It depends on who controls the premises and the water system. A managing agent with real control of a building's shared systems can be a duty holder in their own right, alongside the landlord or freeholder. The lease or management agreement should allocate responsibility explicitly. What is not possible is for everyone to assume someone else holds the duty: where control is shared, each party holds it for what they control.
What is a competent person for legionella?
A competent person is anyone with enough knowledge, training and experience to do a specific legionella task properly: carrying out a risk assessment, taking samples, servicing a thermostatic mixing valve or running the monitoring. It describes a quality, not a job title. The responsible person must be competent for their role, and anyone brought in to help must be competent for theirs, but the same individual does not have to be competent at everything.
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