A Legionella risk assessment is an essential part of being a landlord, but it receives far less attention than many of the other legal requirements and responsibilities that landlords face.

The wording of the legislation governing Legionella testing has also caught landlords off guard in the past, so today we’ll take a deep dive into water safety and hopefully bring some clarity to this sometimes-confusing subject.

Before we get into what landlords must do, let’s take a quick look at Legionella to see why it’s such an important topic to be aware of.

What is Legionella?

In a nutshell, Legionella is a bacteria that can cause Legionnaires’ disease, a severe form of pneumonia. Legionnaires’ disease is primarily a water issue in the United Kingdom, but it can also be contracted by inhaling Legionella bacteria from soil.

Legionella bacteria, like any living organism, requires a specific environment to thrive. Modern water systems are ideal habitats for Legionella, particularly when left unattended for an extended period of time, because they meet the bacteria’s temperature requirements and provide food in the form of sludge, rust, scale, and/or biofilm.

The landlord must pay close attention to the hot and cold water systems.

What are the Legionnaires’ disease symptoms?

According to the Mayo Clinic, the following can be expected from those who have contracted Legionnaires’ disease:

Legionnaires’ disease usually develops two to 10 days after exposure to legionella bacteria. It frequently begins with the following signs and symptoms:

• Headache
• Muscle aches
• Fever that may be 104 F (40 C) or higher

By the second or third day, you’ll develop other signs and symptoms that can include:

• Cough, which might bring up mucus and sometimes blood
• Shortness of breath
• Chest pain
• Gastrointestinal symptoms, such as nausea, vomiting and diarrhea
• Confusion or other mental changes

Although Legionnaires’ disease mostly affects the lungs, it can also infect wounds and other parts of the body, including the heart.

Pontiac fever is a mild form of Legionnaires’ disease that causes fever, chills, headache, and muscle aches.

Who is the most vulnerable?

Legionnaires’ disease is a type of pneumonia, which is an infection that causes inflammation in the lungs. It should come as no surprise that older people and those who have a history of smoking are the most vulnerable. Those with weakened immune systems are also more likely to contract Legionnaires’ disease.

What are the legionella legal requirements for landlords?

Landlords have a legal obligation to provide their tenants with a home that is both safe and free of health hazards. Naturally, this includes determining the risk of Legionella exposure.

However, according to the Health and Safety Executive (HSE), this does not necessitate the creation of a professional assessment report, so landlords are free to conduct their own Legionella risk assessment (more on which later).

Are older buildings more susceptible to Legionella?

In a way. Older homes may have older water systems, which may provide a better breeding ground for the bacteria, but Legionella colonisation can also occur in relatively ‘new’ hot and cold water systems.

As a result, old water systems that have been regularly maintained and kept in use for their entire lifespan should pose no greater risk than a newer system. In fact, a neglected newer water system poses a greater risk because it has not been flushed or the water contained within it has not been kept moving.

It should also be noted that water storage plays a significant role in the formation of Legionella bacteria. Water drawn directly from the mains supply, for example, by a combi boiler, reduces the risk of Legionella significantly. As a result, replacing old water heaters with new ones can have a significant impact on a property’s risk potential.

Carrying out a Legionella risk assessment

Fortunately, conducting a Legionella risk assessment isn’t too difficult, and, as previously stated, landlords are free to conduct the assessment themselves if they feel competent and knowledgeable about Legionella and the risks the bacteria poses.

If the landlord does not believe they have the necessary skills to properly assess the Legionella risk, or simply does not want to perform the assessment themselves, a professionally trained or accredited contractor can be called in to complete the task.

A Legionella risk assessment is usually simple, straightforward, and uncomplicated. Knowing the risks associated with hot and cold water systems, as well as the factors that allow Legionella to thrive (see below), will enable landlords to make an honest assessment and implement the necessary preventative measures to reduce the risk of colonisation.

What exactly is a Legionella assessment?

The following are common steps taken when performing a Legionella risk assessment:

• A close inspection of all water systems within the property
• Determining likely hazards and assessing the risk level of each
• Pinpointing who is at risk
• Making a written record of the findings

From here, the necessary control measures can be identified and implemented to reduce the risk of Legionella colonisation.

The above points are from a Legionella self-assessment of water systems. If you hire a professional assessor, you can expect them to perform water tests on samples taken from the system. Although not legally required, most professional Legionella inspections include this extra precautionary step.

How frequently must landlords assess Legionella risk?

Another murky area of Legionella legislation is how frequently landlords must conduct risk assessments for the bacteria. The term “periodically” is used, and the HSE recommends pairing it with other mandatory inspections, particularly in properties where gaining access is difficult.

The HSE states in their documentation that there is no legal requirement to conduct assessments annually or biennially, but it is a good idea to be as proactive as possible. Once every couple of years is a good rule of thumb, but don’t forget to conduct an assessment whenever work is done on the water system or when a tenancy ends and new tenants move in.

Risk factors for Legionella contamination

As previously mentioned, certain factors are required for the bacteria to thrive. Unfortunately, domestic hot and cold water systems provide the necessary building blocks for bacteria to take hold, but the risk of serious contamination and colonisation is greatly increased by the following factors:

• Water temperatures of between 20°C and 45°C
• The presence of ‘food’, such as sludge, rust, scale, biofilm
• Areas where water is aerated, misted, sprayed, or otherwise dispersed into the air
• Water being allowed to ‘sit’ for prolonged periods of time
• Tanks not being flushed or cleaned regularly enough
• Recirculation of stagnant water through the system

Legionella risk reduction: What you should do

Regardless of the results of your Legionella risk assessment, controlling any potential exposure should be your top priority. Fortunately, this isn’t too difficult to accomplish, so there’s no reason not to take the steps outlined below to reduce the Legionella risk in your properties:

• Service your boiler annually and perform routine pipework checks
• Prevent debris from building up within the system
• Frequently check seals on water tanks
• Remove any redundant pipework
• Flush the system regularly to ensure no water is left sitting. Stagnant water must be removed from the system, so void periods are times when landlords should be especially vigilant
• Keep water temperatures outside of the breeding range. Water kept at 60°C will not only prevent growth, it will also kill any Legionella bacteria present in the system

If you’re thinking about installing a new water system or if your old boiler has given up the ghost, consider switching to instant water heaters and getting rid of your water tanks entirely. This simple step will significantly reduce the likelihood of Legionella colonisation in your rental.