Legionella risk assessment for landlords: what the duty actually is

A legionella risk assessment for landlords is an assessment of the water system in a let property, written down, kept, and reviewed when something changes. Two myths surround it: that every property needs laboratory water testing, and that a certificate is required. Neither is generally true for a normal domestic let — what is required is that the risk has been assessed by someone competent and that the assessment exists in a form you can produce.

What a legionella risk assessment for landlords looks at

• The type of system: a modern combination boiler with no stored water is a very different risk from a stored hot water cylinder and a cold water tank.
• Water temperatures — hot water hot enough, cold water cold enough, measured rather than assumed.
• Dead legs and unused outlets, including an en-suite nobody uses and an outside tap fed from the main system.
• Debris, scale, rust or biofilm in tanks and cylinders where they exist.
• Showers and spray outlets, which produce the aerosol that matters.
• Void periods, because a property standing empty is the most common way risk is created.
• Vulnerability of the occupants where you know it — the consequence side of the risk, not the likelihood.

Who can carry it out

For a straightforward domestic property a competent landlord or agent can do the assessment themselves; competence here means understanding the system and the control measures, not holding a qualification. Complex systems, communal water in a block, cooling towers or care settings are a different matter and belong with a specialist. Note what the search results will push at you: most paid advertising in this area is assessment companies buying leads, which is a legitimate service but not a legal requirement for a simple let.

There is no statutory "legionella certificate" for a domestic tenancy. If a service offers you one as a legal necessity, you are buying reassurance rather than compliance.

The control measures that do the work

1. Keep hot water storage above the design temperature and make sure it reaches the outlets.
2. Keep cold water below the threshold at the outlets, not just at the mains.
3. Remove redundant pipework rather than capping it, because a dead leg is a reservoir.
4. Flush all outlets, including showers, before a new tenancy and after any void of more than a week.
5. Descale and disinfect shower heads and hoses on a stated interval.
6. Tell the tenant what they need to do — flush after holidays, report water that runs lukewarm, keep the thermostat where you set it.
7. Reassess when the system changes, the property is empty for an extended period, or the occupancy changes materially.

What to keep, and where

The assessment, the date, who carried it out, the control measures chosen, and the record of each flush, temperature check or clean with its date. That is a register, not a document: one row per property with the assessment attached and the monitoring entries beneath it. Ettex Records is a practical home for it, and it sits naturally next to the rest of the landlord compliance file — gas, electrical, alarms, deposit — so that "show me this property's file" is one screen rather than four.

Where landlords get caught out

• No written assessment at all, on the basis that the property is "obviously low risk" — which may be true and is still not an assessment.
• An assessment from five years ago and a boiler replaced since.
• A void period with no flushing record, then a new tenant in a system that stood still for two months.
• Instructions given to the tenant verbally at check-in and never written down.
• Paying for quarterly sampling on a combi-boiler flat, which is money spent on the wrong risk.

For anything beyond a single dwelling — a block with communal hot water, a care setting, a business premises — the duty is heavier and the monitoring regime is explicit; the legionella testing requirements for those systems are a separate subject from the domestic assessment described here.