The law has changed recently and now requires landlords to undertake an assessment on their residential properties to identify the risk of legionella.

What is legionella?

Legionella is a bacteria which lives in water systems like water tanks, air conditioning units and humidifiers. When breathed in, water droplets containing the bacteria can cause Legionnaires’ Disease.

What do landlords need to do?

The new legislation states that landlords need to have a “competent person” undertake a risk assessment and identify if there are areas in which water could lie for long periods of time (the main risk factor for growth of the bacteria). Landlords can undertake this assessment themselves if they believe they are competent to do so, or they can instruct a specialist contractor to do it for them.

To comply with the law, landlords and agents need to be aware that legionella bacteria can multiply in hot or cold water systems and storage tanks, and be spread via showers and taps. Risk assessments must identify and assess potential sources of exposure, and steps take to prevent or control any risk that is identified. Risk assessments can normally be carried out by agents or landlords, and include assessing whether conditions are right for bacteria to flourish – in water tempteratures between 20C and 45C. Areas of stagnant water, infrequently used outlets, debris in the system, and thermostatic mixing valves should all be inspected. However, the part of the risk assessment likely to cause most problem is whether any particular tenants, such as older people or those already ill, might be vulnerable to infection. Landlords and agents will also have to balance one set of advice – to raise the temperature of warm water to control legionella – against the risk of possible burns and scalding. Steps taken to control the threat of legionella include disinfecting the system, ensuring no water can stagnate anyway, insulating pipework, and keeping water cisterns covered and free of debris. Tenants should also be advised about risks, and told to take precautions such as flushing through showers they rarely use.

What happens if a landlord fails to address this issue?

There are fines for landlords who don’t comply with the regulations. Legionnaires’ Disease can be fatal, and landlords have a legal obligation to ensure that their tenants and others visiting the property are protected.
The Health and Safety Executive has published guidance for landlords, which is available online at