Legionella Risk Assessment for Landlords

# Legionella Risk Assessment for Landlords

Legionnaires disease is a severe form of pneumonia caused by inhaling water droplets containing Legionella bacteria. Around 500 cases are reported in the UK each year, and around 10% are fatal. Landlords have a legal duty to assess and control the risk in their properties under the Health and Safety at Work Act 1974 — but the assessment for a typical AST is far simpler than scaremongering companies suggest.

What the law actually says

The Health and Safety Executive Approved Code of Practice L8 applies to "any premises controlled in connection with a trade, business or other undertaking". HSE confirms in writing that landlords fall within this — letting property is a business.

You must:

1. Identify and assess sources of risk.
2. Manage the risk.
3. Prevent or control the risk.
4. Keep and maintain records.
5. Appoint a competent person.

You do NOT need to:

• Carry out laboratory water sampling for a low-risk domestic property.
• Hire a "Legionella specialist" for every property.
• Renew certificates annually unless the system changes.
• Pay £150 for a one-page "Legionella certificate" — these are often a scam.

Where Legionella grows

Legionella thrives in water that is:

• Stagnant — unused outlets, dead legs in pipework.
• Warm (20–45°C) — tank-fed hot water systems, sun-warmed pipes.
• Aerosolised — showers, taps with spray, hot tubs.
• Contains scale, rust or biofilm — old galvanised tanks.

It does NOT grow in:

• Properly heated water above 60°C.
• Cold mains water below 20°C.
• Frequently used outlets.

Risk level by system type

The DIY assessment for a typical rental

For a single-family flat or house with combi boiler:

1. Walk through and identify every water outlet.
2. Confirm cold water is mains-fed (turn off mains and check taps stop).
3. Confirm hot water comes from a combi boiler (no tank, no cylinder).
4. Check thermostat is set to 60°C+ on a cylinder if present.
5. Identify dead legs (capped pipes, removed appliances).
6. Note infrequently used outlets (en-suite shower, garden tap).
7. Write up the findings on a one-page template.
8. Brief tenants on flushing little-used outlets weekly.

When to call a specialist

• Cold water tank in loft (most pre-1990s houses).
• Hot water cylinder over 5 years old.
• HMO with 5+ tenants and shared bathrooms.
• Property has been empty more than 2 months.
• Any sign of scale, rust, brown water, or smell.
• Hot tub, spa, swimming pool, water feature.

Specialist costs:

• Domestic risk assessment: £75–£150.
• Sampling 4 outlets + lab test: £150–£300.
• Full HMO survey: £300–£600.

What to tell tenants

Provide written guidance at check-in:

• Run all taps and showers for 2 minutes after any period the property was empty (e.g. when returning from holiday).
• Flush little-used outlets (en-suite shower, garden tap) weekly.
• Set hot water cylinder thermostat to at least 60°C — do not turn it down.
• Clean and descale showerheads quarterly.
• Report any brown water, smell, or thermostat issues immediately.

A tenant-friendly version of this fits on one A4 sheet — Smart Sleep Property issues it automatically with new tenancies.

Between-tenancy actions

When a property is unoccupied for more than 2 weeks:

1. On re-entry, run all hot and cold outlets for 2 minutes.
2. Run shower for 2 minutes with shower head submerged in a bucket of water (to avoid aerosolising bacteria) or removed.
3. Flush WC twice.
4. Note in your records.

Record keeping

Keep on file:

• The risk assessment (one page is fine for low-risk properties).
• Tenant guidance issued.
• Inspection / flushing log for void periods.
• Any specialist reports.
• Review date (2 years for low-risk, annual for medium/high).

What HSE expects in an inspection

HSE rarely inspects domestic properties unless there is a notifiable disease case. After a confirmed case linked to a rental, expect:

• Full risk assessment review.
• Water sampling.
• Interview with the landlord.
• Potential prosecution under section 3 of the Health and Safety at Work Act.

Maximum penalty: unlimited fine and 2 years imprisonment.

Common misconceptions

• "I need a Legionella certificate every year" — false. Two years for low-risk.
• "I must hire a registered assessor" — false. Competent landlord can DIY.
• "It only matters in commercial properties" — false. ACoP L8 applies to all landlords.
• "Combi boilers can't have Legionella" — almost true (mains feed + no storage), but never zero.

Use the Smart Sleep Property Legionella Risk Assessment template in the Landlord Tools centre to complete yours in 20 minutes.