How To Remove Legionella From Water: A Guide

Did you know Legionnaires' disease got its name from the 1976 outbreak at the Legion convention in Philadelphia? Fourteen of the attendees reported experiencing mysterious symptoms and contracted pneumonia. Unfortunately, six of these 14 people died due to the disease, and at the time tests couldn't determine the cause for the illness.

With the possibility of contracting Legionnaires' disease, it is important to know how to remove Legionella from water. Keep reading to see what you can do to prevent Legionella from spreading.

What Is Legionella?

Legionella is a bacteria commonly found in water. It multiplies in temperatures between 68°F to 113°F, but the bacteria can't survive temperatures above 140°F.

If you inhale airborne water droplets that contain the Legionella bacteria, you could contract Legionnaires' disease. Legionnaires' disease can't be passed from person to person. It can only be contracted by coming in contact with contaminated water.

What Is Legionnaire's Disease?

Legionnaires' disease is a potentially fatal type of pneumonia. It has a fatality rate of 10% in healthy people, and it increases to 25% for people with underlying conditions. In the United States, over ten thousand people are hospitalized with Legionnaires' disease every year.

While legionella bacteria is sometimes found in the soil and water outside, it is rarely infectious. But water systems are a breeding ground for bacteria.

It is possible to contract Legionnaires' disease from your home plumbing, but most outbreaks are found in larger buildings. The HVAC systems of these buildings are more complex, which allows the bacteria to spread more easily.

Legionnaires' disease develops between two and ten days after bacterial exposure. The following Legionnaires’ disease symptoms are common:

• Headache
• Muscle aches
• Fever that may be 104 F (40 C) or higher
• By the second or third day, symptoms usually evolve to also include:
  • Cough; this may bring up mucus or even occasional blood
  • Shortness of breath
  • Chest pain
  • Gastrointestinal issues and symptoms, including nausea, vomiting, and diarrhea
  • Confusion or other mental changes

Because most of these symptoms are common and shared by several illnesses, it is difficult to diagnose someone with the disease. So, it is mainly discovered when there is a larger outbreak, and many people show the same symptoms.

There is also a mild form of the disease called Pontiac fever. Pontiac fever can cause fever, chills, headaches, and muscle aches. But, the fever doesn't infect your lungs in the same way that Legionnaires' disease does, and symptoms start fading after a few days.

How Do You Test A Person For Legionella (Legionnaires’ Disease)?

The most common test for Legionella — or, in the case of a person who has Legionnaire’s Disease — is a urinary antigen test. The test determines whether there are Legionella bacteria in the patient's urine. If the test is positive and the patient is showing signs of pneumonia, the doctor will typically confirm a Legionnaires’ Disease diagnosis.

How Do You Remove Legionella From Contaminated Water Systems?

To start off, you or your company need to carry out a full risk assessment of your water systems. You should be thinking about your water systems from the perspective of a hypothetical Legionella contamination.

1. What water safety measures do you already have in place?

2. When was the last time your water was tested?

3. How about your HVAC system? When was the last time that was checked for any standing water?

4. Where are the most likely places in your specific water system that Legionella could grow?

You need to know that Legionella bacteria is present before you start any Legionella treatment plan.

Testing for Legionella

Here is the CDC’s official testing procedure and recommendations for potential sampling sites. This won’t replace the need for a proper inspection, but it’s a fantastic resource for understanding Legionella.

Testing Methods

The method for testing water for Legionella may vary depending on the type water system being tested, the size of the sample, and the instruments the testing lab has on hand.

Traditional Culture

In a traditional culture test, the sample is put onto a plate that is then placed in an incubator. The incubator is set to the perfect temperature for bacteria to grow.

Once the bacteria has had time to grow, the sample is inspected with a microscope for the presence of Legionella bacteria.

This test will detect all species of Legionella, and the results are typically reported as colony forming units per unit volume.

The downside of traditional culture tests is that its efficacy is dependent upon the skill and precision of the laboratory.

Traditional culture test results are usually available in a week or two.

PCR

PCR tests look for Legionella DNA or RNA in a sample. These results are usually available much faster than traditional culture tests — usually within a day or so.

One kind of good — but kind of bad — aspect of PCR tests is that the test is unable to determine whether any bacteria it detects is alive or dead.

It’s entirely possible that a successful treatment or very mild contamination still might cause a sample to test hot for Legionella.

That’s the bad news.

The good news is that PCR tests are fantastic baseline tests. They’re also great at the end of a treatment job to confirm for the complete absence of Legionella bacteria.

Important Note!

The results of any test for Legionella aren’t an exhaustive evaluation of any health risk, and any Legionella is too much Legionella.

Any positive test is an urgent concern.

Remember: if a Legionella contamination’s source isn’t treated, the contamination will persist and illnesses will likely reoccur.

Treating Legionella Contamination

The first method you (or, more likely---the Legionella treatment company you hire) will use is Legionella prevention in hot water systems through temperature control. Since the bacteria can't survive temperatures above 140°F, all hot water storage cylinders should store the water at a higher temperature. Similarly, cold water should be stored at temperatures below 68°F.

You need to identify any 'sentinel' outlets, usually, they will be the closest and farthest outlets to each tank or cylinder on your property. These outlets need to be checked monthly to determine if the distribution temperatures prevent the Legionella bacteria from growing.

Have a Legionella Control Plan

While the best way to ensure you are safe from Legionella is prevention and water treatment, having a Legionella control system is crucial. Knowing what to do if Legionella is detected can save someone's life, not to mention keep your business open.

Generally, someone will fill the role of Legionella risk manager. Typically, this person is appointed by — or is — your facility’s EHS manager.

The Legionella risk manager not only needs to be organized and rigorous, but they will likely need specific experience or training in dealing with Legionella. Here are some places to go for Legionella training.

If you or your company don't have a Legionella risk manager, you can contact Legionella specialists like ReadyLimit. We can help you design and implement a Legionella safety plan. Drop us a line.

Design Systems to Minimise Legionella Growth

The best way to manage control of Legionella bacteria in water systems is to design your water systems in such a way that it hinders bacteria growth. Here are a few ideas:

• Keep your pipe runs as short and direct as possible to prevent Legionella in water pipes
• Insulate your pipes and tanks to keep them at optimal temperatures
• Choose construction materials that don’t encourage Legionella growth
• Remove old, disused piping wherever possible. Legionella loves to grow in stagnant water.
• Look for rarely used water outlets. Same as old pipes: Legionella just needs standing water and warm temperatures.
• Flush your piping system regularly to eliminate stagnant water. You should be doing this anyway, right? Flushing piping systems helps make sure that they’re all working as expected.

Prevent Legionnaires Disease

By following these guidelines and staying on top of maintenance, you should be on top of your Legionella prevention and water treatment plan.

Legionella contamination is rare in modern, well maintained HVAC and water systems. Nevertheless, facilities, buildings, and water systems infected with legionella are a serious health hazard and should be taken seriously.

Having a safety and prevention plan isn't just the smart choice — it's the only responsible choice.

Contact us today for more information on how to remove Legionella from water, as well as help design Legionella safety plans.