Protecting families from contaminated food and water
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Protecting families from contaminated food and water
Posted in Legionella,Legionnaire's disease,Our Blog on July 31, 2025
Legionnaires’ disease in flood water is a growing concern as homes and water systems become compromised.
As Texas recovers from catastrophic floods, and other areas across the country receive historic amounts of rainfall, it is a great time to talk about Legionnaires’ disease in flood water and what you can do to prevent illness.
But first, what is Legionnaires’ disease, and what does it have to do with flood water?
Legionnaires’ disease is caused by inhaling microscopic Legionella bacteria.
This often happens when these bacteria contaminate a water supply and become suspended in aerosolized water droplets. A water mist of sorts.
Inhaling this mist can move these waterborne bacteria into your lungs where they can cause infection.
While this bacterium is naturally occurring in freshwater environments (lakes, streams, etc.), they can also grow in human-made water systems. In fact, that is how most Legionnaires’ disease infections take place.
Certain human-made water systems are better suited for growing and spreading harmful Legionella bacteria. But anything that generates a mist or spray can spread these germs.
Common sources of Legionnaires’ disease include:
While hot tubs and cooling towers are historically the most likely source of Legionnaires’ disease outbreaks, The Alliance to Prevent Legionnaires’ Disease explains that “drinking water system are the primary source of Legionella bacteria.”
In fact, The Centers for Disease Control and Prevention (CDC), World Health Organization (WHO), U.S. Environmental Protection Agency (EPA), and the U.S. Veterans Health Administration (VHA) each list drinking water systems as the primary source of Legionella and Legionnaires’ disease.
So, what does this have to do with flood water?
Contamination.
Contaminated fresh water sources mixing with municipal water systems can expose the entire system to harmful Legionella bacteria.
Once contaminated, these hardy microbes build their own protective biofilm to resist treatment while continuing to grow and reproduce.
Contamination can come at the source, with downstream contamination of municipal water tanks or holding areas.
Or it could come from breaks in infrastructure, which could allow flood water to enter the system. Cracked or broken pipes can leach in external water, bringing contamination to homes through faucets.
Someone showers, washes dishes, or fills a water glass. This produces a brief mist. They breathe in bacteria. Infection occurs.
When flood water enters your home, it creates an entirely new set of complications.
Contaminated water from springs, lakes or rivers may mix with flood water, bringing those outside germs inside with them along with the flood water.
Even if a body of water is not nearby, Legionnaires’ disease in flood water is still a significant risk. Legionella bacteria also naturally occur in the soil. When soil is disturbed from hard rain or mixed into flood water, those bacteria can hitch a ride and make their way to wherever the water takes them.
Legionella bacteria are not only responsible for Legionnaires’ disease, but also for another type of “self-limited flu-like illness.”
Pontiac Fever.
Pontiac Fever is a milder illness associated with Legionella bacterial infection.
Legionnaires’ disease is a whole other story!
The majority of Legionnaires’ disease cases are not part of a wider outbreak. Most Legionnaires’ disease cases require hospitalization. Small exposures here and there are a significant part of the 8,000 to 18,000 hospitalized with the illness each year. These illnesses can be fatal.
1 in 10 individuals with Legionnaires’ disease will die from complications of their illness. In a health care setting, this risk elevates to 1 in 4.
Anyone who is exposed to Legionella bacteria can become sick. However, certain groups of people are at higher risk of becoming infected if exposed.
As with most illnesses, those with a weakened immune system are at higher risk of becoming sick. As are current and even former smokers and those with chronic lung conditions. Conditions like Chronic Obstructive Pulmonary Disease (COPD) or emphysema. Those over 50 years of age are also at greater risk of illness after exposure.
Contaminated water mist is pretty much the only way to become sick with Legionnaires’ disease. Unlike other respiratory illnesses, you cannot get it from another infected person.
While there has been a hand full of reports of this type of transmission, occurrence is extremely rare. Other factors likely contributed to those situations.
Legionnaires’ disease generally produces respiratory and flu-like symptoms. In fact, it is often underdiagnosed. Unless specific tests are performed, most physicians treat the illness like typical phnemonia.
Common symptoms of Legionnaires’ disease include:
These symptoms usually begin around 2 to 14 days after exposure. However, in some cases, illness may take longer to present.
Other symptoms may include diarrhea, nausea, and/or confusion.
If you are exposed to Legionnaires’ disease in flood water, there are a few thing you can do to help protect yourself and your family from infection.
If you live in an area that has recently experienced flooding, you may have Legionella bacteria in your water supply.
Even if you are not currently under a “boil water notice,” it is a good idea to boil water to ensure it is safe to drink, cook with, wash hands, etc.
Carefully transfer water to a pot to boil. Avoid breathing in mist or splashes while doing this.
Bring water to a rolling boil for at least one minute.
Allow water to cool before using it.
If you must enter flood water, take care to avoid spashing.
Move slowly and carefully to avoid aggressively disturbing water. Your goal is to avoid splashing, misting, or spraying.
If possible, evacuate the area. Remove yourself from the area until the water subsides to reduce exposure to Legionella bacteria.
If you’d like to know more about food safety topics in the news, like “Legionnaires’ Disease in Flood Water is a Growing Concern,” check out the Make Food Safe Blog. We regularly update trending topics, foodborne infections in the news, recalls, and more! Stay tuned for quality information to help keep your family safe, while The Lange Law Firm, PLLC strives to Make Food Safe!
By: Heather Van Tassell (contributing writer, non-lawyer)