The Complete Guide to Legionella management for landlords, businesses

Before we get into Legionella risk management, we’ll focus on why it is so important. In this chapter, we will answer the question: “What is Legionnaires’ disease?”

What is Legionnaires’ disease?

Legionnaires’ disease is a severe form of pneumonia caused by Legionella bacteria. The bacteria cause inflammation of the lungs. The condition can cause long term health problems, and even death.

When was Legionella discovered?

Legionnaires’ disease got its name from the first known outbreak of the condition, which occurred in Philadelphia, USA in 1976. An American Legion convention was held at the Bellevue-Stratford Hotel, with over 2,000 members of the Legion in attendance. Within a week of the end of the convention, five attendees had died, and six died a few weeks later, all with similar symptoms.

Contracting Legionnaires’ Disease

Legionnaires’ isn’t spread from person to person, but from the inhalation of contaminated droplets of water in the air which contains the Legionella bacteria.

In every instance of the disease, the affected person would have inhaled droplets of the contaminated water supply in mist or spray form.

How Legionnaires’ Is Spread

Where Can Legionella Be Found?

Legionella bacteria can be found in natural water sources, and can also make its way into human-made water systems.

Can Legionella Survive Out Of Water?

Legionella bacteria can be found in natural water sources, and can also make its way into human-made water systems.

The Spread Of Legionella Bacteria

Low levels of Legionella are generally not a cause for concern, but if a water source becomes contaminated to unsafe levels, anyone who encounters that water source is placed at risk. Any system that produces a spray or mist (causing inhalation of water droplets) poses a risk.

Can You Get Legionella From Drinking Water?

Legionnaires’ disease is caused by inhaling infected droplets of water, so it can only develop in the respiratory system. Although it’s unlikely, you could potentially inhale infected drinking water if you cough or splutter while drinking it.

Can You Get Legionella From Air Conditioning?

You could only be exposed to Legionella via air-conditioning if your air conditioning uses a water-based system of cooling which then becomes infected with the Legionella bacteria or if the system has been contaminated from elsewhere in the building.

Who Is Most At Risk Of Catching Legionnaires’ Disease?

Most people who are exposed to Legionella do not become ill; some people are at greater risk of developing Legionnaires’ disease.

Risk Factors Include

The Symptoms Of Legionnaires’ Disease

Early symptoms of the disease include:

• Muscle aches
• Tiredness
• Headaches
• Dry cough

These flu-like symptoms typically occur between two and ten days after exposure to Legionella bacteria.

As the disease progresses, other symptoms more indicative of pneumonia begin to appear:

• Green phlegm
• Shortness of breath
• Chest pain
• Confusion

How Legionnaires’ Disease Is Diagnosed

A chest x-ray will confirm if pneumonia is present. Samples of both urine and phlegm can be taken to test for the presence of the Legionella bacteria.

Is Legionnaires’ Disease Fatal?

Although the average mortality rate of Legionnaires’ is 10%, the mortality rate is dependent on the population infected. For example, outbreaks in hospitals or care homes may have a higher mortality rate since it will infect people who are elderly or already compromised.

Legionnaires’ Disease Treatment

Antibiotics are administered to kill the Legionella bacteria. Many people diagnosed with Legionnaires’ disease will go into hospital to be treated so that antibiotics can be delivered via a drip.

Depending on the severity of the condition and the diagnosis and treatment timelines, recovery may take several weeks or months. In serious cases, people have reported lasting effects such as fatigue, neurological symptoms, and neuromuscular conditions.

Legionella can multiply at an extremely fast rate, especially in stagnant water at the right temperature. That’s why regular flushing and monitoring of hot and cold water temperatures is crucial with regards to controlling Legionella growth in a water system.

Testing For Legionella Compliance

As with your Legionella risk assessment, a competent and qualified person within your organisation or a third-party specialist can test your water systems.

How To Test For Legionella In Water

The primary method used to control the risk from Legionella is water temperature control.

As discussed, you need to test the temperature of your water systems to avoid water reaching the right temperature for Legionella bacteria to proliferate (between the temperature range of 20°C and 45°C).

Legionella And Temperature

Legionella bacteria require specific temperature conditions to survive and multiply:

Because Legionella only survive and multiply within a specific temperature range, keeping water temperatures below or above this can help mitigate the risks of Legionella infection.

Water Temperature To Prevent Legionella

Check The Sentinel Outlet

The sentinel outlet is the tap that is located at the nearest and furthest point from the calorifier, water heater (for hot water) or the source (for cold water).

How To Carry Out Legionella Temperature Testing

There are two ways to carry out water temperature testing – manually taking the temperature at sentinel outlets at regular intervals, or installing a smart system that can take temperatures automatically at predefined intervals.

First, we’ll look at the more labour- and time-intensive manual testing.

Manual Legionella Control Testing

How To Check Your Hot Water Temperature To Control Legionella Risks

1. Turn on the sentinel outlet for your hot water.
2. Hold a thermometer under the running water for at least a minute.
3. Ensure that the temperature reaches at least 50°C.
4. Record the temperature.

If the temperature doesn’t reach 50°C within one minute, report it to the responsible person to take remedial action.

How To Check Your Cold Water Temperature To Control Legionella Risks

1. Turn on the cold water sentinel outlet.
2. Hold a thermometer under the running water for at least two minutes.
3. Ensure that the temperature reaches below 20°C.
4. Record the temperature.

If the temperature is not below 20°C within two minutes, report it to the responsible person to take remedial action.

How Long Should I Run Water To Prevent Legionella?

How Often Should Legionella Temperature Testing Be Carried Out?

At the very least, testing should take place:

Truly effective monitoring for risk of Legionella requires constant, real-time water temperature checks. This is made possible through automated flushing and temperature checking.

Recommended Legionella Flushing Regimes

FAILED OUTLETS

The minimisation of aerosol must be achieved by placing a plastic bag with a corner cut off, secured over the tap outlet.

LITTLE USED TAPS

Any little used taps should be flushed for a minimum of 2 minutes on a twice weekly basis (avoid splashing to minimise the creation of aerosol).

LITTLE USED SHOWERS

Any little used shower outlet must be flushed through for a minimum 2 minutes on a twice weekly basis.

LITTLE USED APPLIANCES

Any little used appliances (E.g. Sluice Machines, Washing Machines etc.) should be flushed weekly (twice weekly for healthcare organisations).

LITTLE USED TOILETS

Any little used toilet outlet should be flushed weekly (the lid should be in the down position to minimise aerosols).

How Much Does A Legionella Test Cost?

Testing can be expensive and inconvenient if it involves regular site visits by an expert.

Comparing Manual Legionella Control Testing To Automated Test And Flushing

Automated Legionella control testing and flushing saves significant time and resources. We’ll discuss automated systems further in Chapter 9.

This infographic compares manual Legionella control testing to automated testing, using the example of a building with two floors and four restrooms.

Checklist: Legionella Management Tasks

All individuals appointed should be properly trained to perform tasks in a safe and technically competent manner. Regular refresher training should be provided and records maintained.

Legionella Control By Design

Legionella growth favours stagnant water and a certain temperature range. To reduce the risk of bacteria growing, you should:

• Remove dead legs/dead ends in pipe-work
• Flush out infrequently used outlets (including showerheads and taps) at least weekly
• Clean and descale shower heads and hoses at least quarterly.
• Clean cold water storage tanks periodically
• Ensure that the release of water spray (e.g. from cooling towers) is properly controlled
• Drain water from hot water cylinders to check for debris or signs of corrosion.
• Avoid water conditions and temperatures that favour the growth of Legionella and other microorganisms
• Keep the system and water clean

Design Systems To Minimise Legionella Growth

• Use only Water Regulations Advisory Scheme (WRAS) approved fittings, materials, and appliances
• Keep pipe work as short and direct as possible to ensure water cannot stagnate anywhere
• Insulate pipes and tanks
• Use materials that do not encourage the growth of Legionella
• Preventing contamination by fitting tanks with lids and insect screens