Multi-Let Offices: Who Is the L8 Legionella Dutyholder?

In a multi-let office building, the question of who is the L8 dutyholder for the water system has a clear answer in guidance and a frequently unclear answer in practice. The gap between the two is where prosecutions begin.

ACoP L8 identifies the dutyholder as the employer or person in control of the premises. HSG274 Part 2 is more specific for shared-occupancy buildings: where there are landlords, leaseholders, tenants, or managing agents, an agreement must be in place detailing the responsibilities of each party. The default position, where no agreement exists, is that the person in control of premises is responsible — and that determination is made by the courts on the facts, not by the lease.

Owner-occupied or full repairing lease. The occupier is the dutyholder for the entire water system. This is the cleanest case in guidance and the one most often misunderstood by tenants who assume building services compliance sits with the landlord because the landlord installed the plant. It does not. A tenant on a full repairing lease who has not commissioned a Legionella risk assessment for the demised water system is non-compliant from the date the lease was signed.

Multi-let building with landlord retaining common parts. The landlord is dutyholder for risers, plant rooms, common-area washrooms, cooling towers serving the building, and any centralised hot water generation. Each tenant is dutyholder for the water services within their demise — typically tea points, kitchenettes, and any tenant-installed showers. Both sides require their own risk assessments. Both sides require their own written control schemes. In practice, the landlord's assessment frequently terminates at the tenant boundary and the tenant assumes the landlord's assessment covers them. Neither assumption is correct, and the building has compliance gaps neither party is monitoring.

Managing agent in place. The managing agent acts on behalf of the owner. Operational responsibility may be delegated. Accountability remains with the owner. A managing agent's appointment letter that does not explicitly assign the L8 dutyholder role leaves the owner exposed if the managing agent's water hygiene contractor fails to perform.

The Barrow-in-Furness outbreak in August 2002 — seven deaths, 180 cases of Legionnaires' disease, traced to a council-run arts centre — turned in part on communication failures between contractor, design services manager, and council. The HSE prosecution under section 3(1) of the Health and Safety at Work Act resulted in a £125,000 fine for the council and a personal £15,000 fine and conviction for the design services manager under section 7. The case is the standard reference point in UK water hygiene law because it established that the dutyholder cannot delegate accountability through a contract, only operational responsibility.

For commercial property directors, asset managers, and FM heads at multi-let portfolios, the operational test is straightforward. Three questions:

1. Is there a written agreement, separate from the lease, identifying the L8 dutyholder for each part of the building's water system?
2. Does the building's risk assessment explicitly map to the demise boundaries, with the tenant boundary clearly marked?
3. Has each tenant produced its own risk assessment for water services within its demise, and is that assessment held by the landlord or managing agent on the building file?

If any answer is no, the compliance position is undefined and the dutyholder will be determined retrospectively by the HSE on the facts of any incident.

A water risk assessment that stops at a riser without identifying who is responsible on the other side of the wall is a half-finished document.

Call us or WhatsApp us on 0800 046 1000 to speak to our expert Plumbing & heating engineers directly for free expert advice.

You can also email the team on [email protected]