Where Are You Most Likely to Catch Legionella?
Posted in Legionella,Legionnaire's disease on April 7, 2026
You are most likely to catch Legionella in large buildings or facilities with complex water systems that produce airborne mist, such as hotels, hospitals, and large buildings. Legionnaires’ disease occurs when contaminated water droplets are inhaled, which can happen when those systems are not properly maintained.
The Most Common Places of Exposure
Legionella grows best in warm, stagnant water and spreads through mist or vapor. The highest-risk locations consistently involve large-scale water systems. The most common places include:
- Hotels and resorts with extensive plumbing systems.
- Hospitals and long-term care facilities.
- Office buildings with cooling towers.
- Apartment complexes and senior housing.
- Cruise ships and large public venues.
These locations create ideal conditions for bacteria growth if water systems are not actively monitored and disinfected.
The Highest-Risk Sources Inside Those Places
Within the most common places of Legionnaire’s exposure, certain water sources are far more likely to spread the bacteria:
Cooling towers stand out as a leading cause of outbreaks because they can disperse contaminated mist over a wide area.
Why Are You Most Likely to Catch Legionella in Large Buildings
Legionella risk increases in systems where water sits, warms, and circulates without proper treatment. Key contributing factors include:
- Water temperatures between 77°F and 113°F, which promote bacterial growth.
- Stagnant or slow-moving water.
- Scale and biofilm buildup inside pipes.
- Infrequent cleaning or disinfection.
Large buildings are especially vulnerable because of their size and the complexity of their plumbing systems.
Types of Negligence Leads to Legionella Exposure
Negligence that leads to Legionella exposure usually involves specific failures in how a water system is managed, maintained, or monitored. Common types include:
- Failing to implement a proper water management program to control bacterial growth.
- Allowing water to sit stagnant in pipes, tanks, or unused areas of a system.
- Keeping water at temperatures that promote growth.
- Not regularly cleaning or disinfecting cooling towers, hot tubs, or storage tanks.
- Ignoring known contamination risks or prior positive Legionella test results.
- Failing to flush unused outlets such as sinks and showers.
- Allowing scale, sediment, or biofilm to build up inside plumbing systems.
- Skipping routine inspections, testing, and maintenance procedures.
Even one overlooked issue can expose many people to contaminated mist.
Who Is Most Likely to Get Sick in These Places?
Exposure does not always lead to illness. However, certain individuals face a much higher risk:
- Adults over age 50.
- Smokers and former smokers.
- People with weakened immune systems.
- Individuals with chronic lung disease.
For these groups, exposure can quickly lead to serious pneumonia.
What to Do If You Were Recently Exposed
If you believe you were exposed to Legionella bacteria, take the following steps:
- Seek medical attention promptly. Inform your doctor that you may have been exposed to Legionella. Early diagnosis and antibiotic treatment can significantly improve your recovery.
- Write down where you have been. Document recent travel, hotel stays, hospital visits, or time spent in large buildings. This information can help trace the source of exposure.
- Keep records of your symptoms and treatment. Save medical reports, test results, and any related expenses. This information may become important later.
- Report the exposure if necessary. Local health departments and agencies like the Centers for Disease Control and Prevention track Legionella cases to identify outbreaks and prevent further spread. However, your doctor should have already done so.
Speaking with a Legionnaires’ disease attorney can also help explain what legal options may be available for recovering compensation.
