Landlords are sold legionella certificates constantly, and the certificate is not what the law asks for. HSE could hardly be clearer: health and safety law does not require landlords to obtain or produce a legionella test certificate. What it does require is that the risk from the water system is assessed and controlled, which is a different thing and usually a cheaper one.
What the duty actually is
A landlord letting residential property is conducting an undertaking, so section 3 of the Health and Safety at Work etc. Act 1974 makes them responsible for the safety of their tenants in respect of it, and COSHH covers the biological agent. The duty is to assess the risk from the water system and to put proportionate control measures in place. For most domestic properties HSE describes those measures as simple, cheap and effective.
What a low risk property looks like
HSE describes it: daily water usage that is inevitable and sufficient to turn over the entire system, cold water direct from a wholesome mains supply with no stored water tanks, hot water from instantaneous heaters or low volume water heaters supplying outlets at 50°C, and outlets limited to toilets and wash hand basins. A simple assessment may show there are no real risks and that they are being properly managed, so no further action is needed.
What actually raises the risk
Stored water in a tank, particularly one without a tight fitting lid. A calorifier not reaching temperature. Showers, because they atomise. Dead legs and redundant pipework left after a conversion. And vacancy, which is why student lets and holiday properties need a flushing regime or draining down. HSE's general principle is that outlets should be used at least once a week to maintain flow and minimise stagnation.
Recording it
HSE states that landlords are not necessarily required to record the findings, because that is a statutory duty for employers where there are 5 or more employees, but that it is wise to keep a record for your own purposes. That record is what you would rely on if a tenant contracted the disease, because the landlord would have to demonstrate to a court that they had fulfilled their legal duty.
Whether anyone will ask to see it
HSE and local authority inspectors do not proactively inspect domestic premises or ask landlords for evidence that they have carried out a risk assessment. Letting agents and insurers often do, which is a commercial requirement rather than a legal one, and it is worth knowing which of the two you are answering when a firm quotes you for a certificate.
Questions people ask about legionella certificate
Do landlords need a legionella certificate?
No. HSE states that health and safety law does not require landlords to obtain or produce a legionella test certificate. The duty is to assess and control the risk.
Is a legionella risk assessment mandatory for landlords?
Assessing and controlling the risk is a legal duty. For a simple domestic system that assessment can be short and can conclude the risk is low and already managed.
Can a landlord do their own assessment?
Yes. HSE says most landlords can assess the risk themselves and do not need to be professionally trained or accredited, and can arrange for someone else to do it if they do not feel competent.
What happens if a tenant catches Legionnaires' disease?
The landlord may be liable to prosecution under the Health and Safety at Work etc. Act 1974 and would have to demonstrate to a court that they had fulfilled their legal duty, which is why keeping a record of what was assessed and controlled matters.