Do you need a legionella risk assessment when buying a property?

No — buying a property does not, by itself, create a legal requirement for a legionella risk assessment, and no such check is part of the standard conveyancing process. The duty attaches to what happens next: if you let the property, employ people in it, or run a business from it, you become a duty holder with obligations under the Health and Safety at Work etc. Act 1974 and ACOP L8, and a risk assessment is the starting point. What the purchase does give you is a natural moment to understand the water system you have just acquired.

Why the question comes up at purchase — and what conveyancing misses

Property lawyers check title, boundaries, searches and building regulation sign-off, but nothing in the standard process examines the water system for legionella risk. A buyer can complete on a building with a dead cold water tank in the loft, a calorifier set to 45°C, and a garden office shower nobody has run in two years, and none of it appears in any report. That is not a criticism of conveyancing — it simply means the water system is one of the things you buy unseen, and the sensible response is a short list of questions and checks of your own rather than an assumption that someone has looked.

What to ask the seller or agent

None of these require specialist knowledge, and the answers sketch the system you are taking on:

• Is there a cold water storage tank? A tank in the loft means stored cold water — the component most likely to warm up and stagnate, and the first thing to inspect after moving in.
• How is the hot water heated, and is there a cylinder? A cylinder or calorifier needs to store at 60°C; a combi boiler stores nothing and carries a lower inherent risk.
• Has the property been empty, and for how long? Weeks or months of emptiness means every outlet has been standing — the trigger for a full flush on moving in, as described in flushing taps after a property has stood empty.
• Are there outlets nobody uses? A second bathroom, a utility tap, an outside shower — each one is a future little-used outlet for the flushing schedule.
• For a previously let or commercial property: is there an existing risk assessment and log book? If so, ask for them. They are a head start on your own assessment — but treat them as history, not cover, because the duty now sits with you.

Buying to let: where the duty actually begins

If the purchase is a buy-to-let, the position changes from sensible precaution to legal duty. Landlords must assess and control legionella risk in let property, and that duty is live from the first tenancy — there is no grace period for new owners, and "I had just bought it" is not a defence that survives contact with an inspector. The practical approach is to complete the assessment in the void period before tenants move in, when access is easy and the flush-and-check routine costs nothing. Our guide to who is responsible for legionella in a rented property sets out the duty, and do I need a legionella risk assessment? covers who the duty catches. The assessment does not have to be contracted out — a competent landlord can do their own — and the risk assessment tool structures the whole exercise.

The first-fortnight routine for any buyer

Whether the property is a home, a let or a business premises, the same short routine establishes your baseline. Flush every outlet to temperature — hot reaching at least 50°C, cold below 20°C — working from nearest the incoming supply outward, with showers run gently or head-off first. Check what the hot water is actually stored and delivered at, using the temperature checker to record the readings. Look in the loft for a tank and check it is lidded, screened and cool. Note every outlet that will be little-used. That handful of observations is most of a simple risk assessment already done, and writing it down — in a log book — turns it from a one-off tidy-up into the start of a record that runs from the day you took the keys.