Legionella Risk Assessments: A Landlord’s Guide to ACOP L8 Compliance

If you own or manage rental or small commercial property in the UK, Legionella compliance isn’t optional; it’s a legal duty. Yet the rules are scattered across a handful of Acts, Regulations, and a Code of Practice that most landlords have never read. Here’s what actually applies, and what it means in practice.

Where the legal duty comes from

Two pieces of legislation sit behind every Legionella Risk Assessment:

• The Health and Safety at Work Act 1974, which places a general duty on anyone responsible for a workplace or rented property to protect the health of people who use it, including tenants and visitors.
• The Control of Substances Hazardous to Health Regulations 2002 (COSHH), which specifically covers biological hazards, including Legionella bacteria in water systems.

Neither of these names “Legionella Risk Assessment” directly. That’s where the HSE’s Approved Code of Practice, ACOP L8, comes in: it sets out exactly what a compliant assessment looks like and how often it should happen.

What ACOP L8 actually requires

Legionella Risk Assessment ACOP L8 recommends that a full Legionella Risk Assessment is reviewed at least every two years, or sooner if anything about the property or its water system changes, a new tenant, an extended void period, a change to the plumbing, or a period where the property has sat empty and outlets haven’t been used.

The assessment itself needs to cover the whole hot and cold water system: tanks, cylinders, pipework, and every outlet, looking specifically for the conditions that let Legionella bacteria grow, stagnant water, incorrect temperatures, and “dead legs” (sections of pipework that see little or no use).

Who this applies to

The duty falls on whoever is responsible for the water system. In practice that usually means:

• Landlords of residential rental properties, including single lets, HMOs, and blocks of flats
• Employers and business owners with a domestic-style water system, shops, offices, small commercial premises
• Letting agents managing properties on a landlord’s behalf, where responsibility has been delegated contractually

It’s a common misconception that only large commercial buildings with cooling towers need to worry about Legionella. In reality, most residential and light commercial Legionella Risk Assessments are for straightforward domestic-style systems, exactly the kind found in a typical rental property.

What happens if you don’t comply

Non-compliance isn’t just a paperwork issue. If a tenant or member of the public were to contract Legionnaires’ Disease and it emerged that no reasonable steps had been taken to assess and manage the risk, a landlord or employer could face prosecution under the Health and Safety at Work Act, alongside the reputational and insurance consequences that follow. A documented, up-to-date risk assessment is your evidence that you took the duty seriously as per Legionella Risk Assessment ACOP L8.

Getting a compliant assessment

A proper Legionella Risk Assessment isn’t a tick-box exercise. It should include an on-site inspection of the whole water system, temperature checks at key points, identification of any dead legs or infrequently used outlets, and a written report with clear, prioritised recommendations, backed by photographic evidence for your records.

If you’re unsure whether your property is due a review, or you’ve never had one carried out, get in touch and we’ll talk you through what’s involved for your specific property.