Legionella Risk Assessments — What the Law Actually Requires (And What Happens If You Ignore It)

A landlord in Birmingham was fined £28,000 last year. Not for anything dramatic — just for failing to carry out a Legionella risk assessment on his rental property. The tenant never got sick. The property looked perfectly normal. But the paperwork wasn't there, and that was enough. If you own a rental property in the UK, this guide will show you exactly what the law requires — and how to make sure you're never in that position.

What is Legionella and Why Should Landlords Care?

Legionella is a bacteria that lives in water systems. When it multiplies and gets inhaled as fine water droplets — from a shower, a tap, or a cooling system — it can cause Legionnaires' disease, a severe and potentially fatal form of pneumonia. In the UK, there are around 300–500 reported cases every year. Many more go unreported.

For landlords, the concern isn't just about tenant health — though that should be reason enough. It's about legal liability. If a tenant contracts Legionnaires' disease and you haven't carried out a risk assessment, you are exposed to criminal prosecution, unlimited fines, civil claims, and in serious cases, imprisonment.

What Does UK Law Actually Say?

The Health and Safety at Work Act 1974 places a legal duty on landlords to assess and control the risk of Legionella in their properties. This is supported by the Control of Substances Hazardous to Health Regulations (COSHH) and the HSE's Approved Code of Practice L8.

In plain English: if you rent out a property in the UK, you must carry out a Legionella risk assessment. This is not guidance. This is not best practice. This is the law.

Many landlords don't know this. Their letting agents don't always tell them. And every day they don't have an assessment, they are exposed.

Where Does Legionella Actually Hide in a Rental Property?

Legionella thrives in water systems where temperatures sit between 20°C and 45°C — the danger zone. In a typical rental property, the highest risk areas are:

• Hot and cold water tanks and cylinders
• Shower heads and hoses — especially those not used regularly
• Taps and outlets that are infrequently used
• Dead legs in pipework — sections of pipe where water sits stagnant
• Properties that have been empty for any period of time

That last point is critical. A property that has sat empty between tenancies — even for just a few weeks — needs its water system flushing and checking before a new tenant moves in. Stagnant water is exactly where Legionella multiplies fastest.

What Does a Professional Legionella Risk Assessment Actually Include?

A professional assessment from a trained specialist — like S2F Property Services — covers everything the HSE requires:

• Full inspection of the hot and cold water systems
• Water tank and cylinder condition check
• Temperature testing at outlets
• Identification of any dead legs or infrequently used outlets
• Shower head, hose and spray fitting inspection
• Assessment of any recent changes to the water system
• A full written risk assessment report you can keep on file
• Clear recommendations for any remedial action required

That written report is your evidence of compliance. It's what you show an HSE inspector. It's what protects you if a tenant ever makes a claim. Without it, you have nothing.

How Often Do You Need a Legionella Risk Assessment?

The HSE doesn't specify an exact frequency — but they're clear that the assessment must be reviewed whenever there's reason to believe it's no longer valid. In practice, that means:

• When a new tenant moves in
• After any plumbing or water system work
• After the property has been empty for an extended period
• After any refurbishment
• As a minimum, every 2 years as best practice

Most professional landlords and letting agents now commission a fresh assessment at the start of every new tenancy. It takes less than an hour, costs a fraction of the potential fine, and gives complete peace of mind.

The Bottom Line

Legionella compliance is one of those things that feels easy to put off — until something goes wrong. The landlord who was fined £28,000 probably thought the same thing. Don't wait for a problem to take it seriously. A professional risk assessment from S2F takes less than an hour, gives you full HSE-compliant documentation, and costs a tiny fraction of what non-compliance could cost you.

We carry out Legionella risk assessments across the UK, 7 days a week, with reports delivered within 24 hours. Book online or call us on 0800 411 8001.