Legionella Risk Assessment for Landlords: What You Actually Need to Do

If you rent out property in the UK, you have a legal duty to assess and control the risk of legionella in your water system. This is not optional — it applies to virtually every rental property with a water system, whether you own one flat or twenty HMOs.

The good news: for most residential properties, the assessment is straightforward and you can do it yourself. Here is exactly what the law requires and how to comply.

What the law actually says

There is no single "Legionella Act." The legal obligation comes from the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health Regulations 2002 (COSHH). These require anyone in control of premises to assess and manage risks from hazardous substances — including legionella bacteria.

ACoP L8 (Approved Code of Practice) translates these obligations into specific requirements for water systems. If you are prosecuted and you did not follow ACoP L8, a court will assume you are at fault unless you can prove you complied another way.

Key point for landlords: HSE confirms that health and safety law does not require landlords to produce a "legionella certificate." There is no equivalent of a gas safety certificate or EICR for legionella. What you must have is a documented risk assessment and evidence of ongoing control measures.

Can you do the assessment yourself?

Yes — for simple domestic hot and cold water systems. HSE explicitly states that most landlords can assess the risk themselves if they are competent to do so.

"Competent" means you understand:

• How your water system works (where water is stored, heated, and delivered)
• What conditions allow legionella to grow (stagnant water, temperatures between 20°C and 45°C, scale and sediment)
• What control measures prevent growth (temperature control, regular use/flushing, cleaning)

For a standard residential property with a combi boiler or stored cylinder, this is learnable. For complex systems (large buildings, cooling towers, stored cold water), engage a specialist.

What the assessment must cover

A compliant landlord legionella risk assessment must document:

1. Building and water system details

• Property address and type
• Water system description: combi boiler, stored hot water cylinder, cold water storage tank, or instantaneous heaters
• Number and location of every water outlet (taps, showers, basins)
• Any dead legs (sections of pipework that lead to removed or capped-off outlets)

2. Hazard identification

For each part of the water system, check:

Hazard	What to look for
Temperature risk	Is hot water stored below 60°C or delivered below 50°C? Is cold water above 20°C?
Stagnation risk	Are there outlets unused for 7+ days? Dead legs? Vacant rooms?
Scale and sediment	Is there visible build-up in tanks, cylinders, or around taps?
Aerosol risk	Are there showers? (Higher risk than taps due to fine water droplets)
System age/condition	Old pipework, corroded tanks, rubber washers or gaskets?

3. Who is at risk

Identify occupants who might be exposed, especially anyone at higher risk: elderly tenants, those with respiratory conditions or weakened immune systems.

4. Control measures

Document what you are doing (or will do) to manage each identified hazard:

• Hot water stored at 60°C or above, delivered at 50°C or above at outlets
• Cold water below 20°C
• Weekly flushing of infrequently used outlets
• Quarterly showerhead descaling
• Void management — flush all outlets before new tenants move in

5. Monitoring schedule

Specify the ongoing checks:

• Monthly temperature monitoring at sentinel outlets
• Weekly flushing of unused outlets
• Quarterly showerhead cleaning
• Review date for the risk assessment itself

6. Responsible person

Name the duty holder — you as the landlord, or someone you have appointed to manage legionella compliance.

What about HMOs?

HMOs carry additional considerations:

• Shared bathrooms — multiple occupants use the same showers, increasing aerosol exposure
• Vacant rooms — when one room in an HMO is unlet, its outlets need weekly flushing
• Tenant turnover — flush all outlets during voids; assess whether the risk profile changes with new occupants
• Modified pipework — HMO conversions often create dead legs where original plumbing was capped off rather than removed

For multi-property portfolios, tracking assessments, review dates, and monitoring schedules across buildings becomes the main challenge.

What inspectors check

Local authority environmental health officers and HSE inspectors will look for:

1. A written risk assessment exists — not just "I thought about it"
2. It is specific to the property — not a generic template filed without review
3. It has been reviewed — dated, signed, with a next review date within two years
4. Evidence of ongoing monitoring — temperature logs, flushing records, showerhead cleaning records
5. Control measures match the risks — if the assessment identifies dead legs, there should be evidence of flushing or removal

The absence of records is treated as the absence of compliance.

What it costs

If you self-assess a simple residential property, the cost is your time — typically 30-60 minutes per property for the initial assessment, plus 15-30 minutes per month for ongoing temperature checks and flushing.

If you hire a specialist, typical costs range from roughly £75-150 for a basic residential assessment, though prices vary by provider, location, and property complexity.

For a multi-property portfolio, self-assessment can significantly reduce costs compared to outsourcing. The ongoing monitoring (temperature logs, flushing) is the same regardless — it cannot be outsourced for a one-off fee.

Get started with a template

LegioLog's Risk Assessment Template Generator creates a landlord-specific template with pre-populated hazards and control measures for your property type. It covers all seven sections required by ACoP L8.

For the full regulatory background, see our ACoP L8 and HSG274 guide. For guidance on review frequency, see how often to review your risk assessment.

This guide covers legionella risk assessment requirements for landlords in England, Wales, and Scotland under ACoP L8. This is general compliance guidance, not legal or professional advice — for site-specific assessments, consult a competent person as defined by ACoP L8.

Sources

• HSE — Legionella and landlords' responsibilities
• HSE — ACoP L8: Legionnaires' disease
• HSE — Identify and assess sources of risk