Do landlords need a Legionella risk assessment?

Short answer: yes. If you rent out a home, you're expected to assess the risk from Legionella and keep it under control. The good news is that for most ordinary flats and houses, it's neither difficult nor expensive.

September's a busy month for lettings. Student houses fill up, new tenancies start, and plenty of properties have sat empty for a few weeks over the summer. So here's a plain-English run through what the law asks of landlords and what a sensible assessment looks like.

What the law actually says

There isn't a single "Legionella law" for landlords. The duty comes from general health and safety legislation:

• The Health and Safety at Work etc. Act 1974 says anyone running a business (and letting property counts) mustn't put other people, such as tenants, at risk through what they do.
• The Control of Substances Hazardous to Health Regulations 2002 (COSHH) treat Legionella bacteria as a hazardous substance that has to be assessed and controlled.
• The HSE's Approved Code of Practice L8 explains how to meet those duties, and it specifically mentions landlords of residential property. Its technical guidance, HSG274 Part 2, covers hot and cold water systems, which is what nearly every home has.

Put together, that means you need to identify and assess the risk, manage it sensibly, and keep a record of what you've done.

Why rented homes are a risk at all

Legionella bacteria live naturally in water at low levels. They become a problem when they multiply, and they do that best in water between roughly 20°C and 45°C, particularly where it sits still and there's scale, sludge or biofilm for them to feed on. People catch Legionnaires' disease mainly by breathing in fine droplets of contaminated water, and a shower is the classic example.

In a typical home the risk is low. A few things push it up, though:

• a cold water storage tank in the loft, especially an old one without a proper lid
• a hot water cylinder that's been turned down too low
• showers, which make exactly the kind of spray that carries bacteria
• pipes to outlets nobody uses, or a capped-off pipe left behind when an appliance was removed (a "dead leg")
• the property standing empty between tenancies
• tenants who are older, unwell or have weakened immune systems

A modern flat with a combi boiler and no stored water sits at the low end. A big old house split into an HMO, with a loft tank and four showers, is a different story.

Do I need a certificate?

No, and be wary of anyone selling you a "Legionella certificate". There's no such legal document, and the HSE has said it doesn't recognise them. What you need is a suitable assessment of the risk, the actions that come out of it, and records showing you've done them.

A written risk assessment is simply the easiest way to prove all that if a council, insurer or investigator ever asks.

Can I do it myself?

You can. The law doesn't insist on a professional. It insists on someone competent, meaning they understand the water system, what makes it risky and what to do about it. For a simple flat, plenty of landlords are happy to do this themselves with the HSE's guidance to hand.

It's worth bringing someone in when the system is bigger or more complicated (tanks, several bathrooms, HMOs, blocks of flats), when you've got a portfolio and want a consistent paper trail, or when you'd just rather know it's been done properly. A visit to a typical flat or house usually takes us under an hour.

What a sensible assessment covers

For a typical rented home, we'd look at:

1. The water system itself. Where the water comes in, whether there's a cold water tank, and how hot water is heated and stored.
2. Temperatures. Hot water stored at 60°C and reaching the taps at 50°C or more within about a minute. Cold water staying below 20°C.
3. Stagnation. Little-used outlets, dead legs, and whether the property sits empty for spells.
4. Condition. Tank lids and insulation, scaled-up shower heads, debris in the system.
5. Who lives there. Vulnerable tenants mean a bit more care is needed.
6. Responsibilities and records. Who does what, and how it gets written down.

You get a short report with a risk rating, any actions in order of priority and a few simple controls to keep things on track.

The simple controls that do most of the work

• Keep the hot water cylinder set so water is stored at 60°C.
• Make sure any cold water tank has a tight-fitting lid and insulation, and get it looked at if it's old or dirty.
• Take out dead legs and redundant pipework when you get the chance. Our remedial works page covers the common fixes.
• Flush the system through before a new tenant moves in if the place has been empty. Run every tap and shower for a few minutes, and keep your face away from the shower head while you do it.
• Give tenants the basics: don't turn the cylinder down, clean and descale the shower head now and then, run any taps that rarely get used, and tell you straight away if the hot water isn't getting hot.

What about testing the water?

Usually it isn't needed. The HSE doesn't expect routine Legionella sampling in ordinary homes. It can help in specific situations, such as after a problem has been found. There's more on that on our water sampling page.

Using a letting agent?

If an agent manages the property, your management contract should spell out who's responsible for Legionella. If it doesn't, assume it's still you. Either way, keep your own copy of the assessment and the records that go with it.

How often should it be redone?

There's no fixed expiry date, but it shouldn't sit in a drawer forever either. Look at it again when something changes, such as new plumbing, a change of tenant type, or the property standing empty for a long spell. We've written a separate guide on how often to review a Legionella risk assessment.

So, do you need one?

If you're a landlord, yes. You need to have assessed the Legionella risk and be keeping on top of it. For most homes that means a short visit, a short report and a few simple habits. If you'd like us to take care of it, or you've got a portfolio that needs bringing up to date, give us a call or send an enquiry. Our maintenance plans can handle the ongoing checks too.