RALEIGH, N.C. (NCN News) – There’s increased concern over a serious respiratory disease that’s on the rise in the Tar Heel State.
The North Carolina Department of Health and Human Services is raising awareness of Legionnaires’ disease as cases have increased statewide and globally in recent years. North Carolina reported 310 cases in 2025 compared to 201 cases in 2024.
Legionnaires’ disease is a serious type of pneumonia caused by a bacteria called Legionella. These bacteria often live in wet environments like natural bodies of water, moist soil and man-made water systems such as hot tubs, decorative fountains, cooling towers, hot water tanks and misting devices that have been poorly maintained.
One of the highest profile incidents of an outbreak in North Carolina was in September 2019 at the Western North Carolina Fair in Fletcher. Four people died and 141 were sickened after attending a hot tub display at the Davis Event Center.
People get Legionnaires’ disease by inhaling mist or vapor contaminated with Legionella, not through person-to-person contact. Most healthy people exposed to Legionella do not get sick, but those at higher risk of illness include:
- People age 50 and older
- People who are current or former smokers
- People with certain health conditions or issues such as chronic lung disease, kidney failure, and diabetes
- People with compromised immune systems
The primary way to prevent Legionnaires’ disease is to control the growth and spread of Legionella in home water systems and in facilities with shared water systems. Steps you can take for prevention in your home include:
- Flush faucets or showerheads if they have not been used for three or more days, or if the home water system was turned off for plumbing work.
- Ensure proper maintenance and disinfection of hot tubs and follow manufacturer guidance.
- Use water following the manufacturer’s recommendations for in-home medical equipment such as humidifiers and CPAP or BIPAP machines. Clean the equipment parts and accessories regularly.
- Follow the manufacturer’s instructions for cleaning and replacing all water filters, including point-of-use filters (tap or refrigerator water/ice maker).
- Drain garden hoses to avoid stagnant water. People at particularly high risk should talk to their doctor about if wearing a mask while doing gardening work would be beneficial.
- Use proper windshield wiper fluid as Legionella can grow in the wiper fluid tank if tap water is added.
Additional steps can be taken in commercial buildings or health care facilities, especially those with cooling towers. While no single measure can ensure Legionella control, following prevention measures can help protect the health of employees and guests by prioritizing water safety:
- Be aware of any unoccupied floors or rooms. Low occupancy decreases water flow, which can decrease disinfectant levels and hot water temperatures. See CDC’s Legionella control considerations for hotel owners and managers website.
- Ensure the building’s water has enough disinfectant and that water is stored at an appropriate temperature. See CDC’s Legionella control monitoring building water website.
- Store cold water at temperatures under 77 degrees Fahrenheit.
- Store hot water at temperatures over 140 degrees Fahrenheit.
- Provide proper maintenance to any hot tubs on site. Legionella can spread in hot tubs due to constant warm water temperatures and aerosolization from water jets.
- Provide proper maintenance of any decorative fountains or misters.
- Cooling tower operators should be aware that Legionella can grow in both open- and closed-circuit cooling tower systems, especially after being idle during colder months. Understanding cooling tower design components are critical for Legionella control:
- Cooling towers should be at least 25 feet from buildings.
- Disinfectant use in cooling towers should be automated.
- A cooling tower’s piping system should be designed to avoid stagnation.
- Operate cooling water towers at the lowest water temperature possible, ideally below 77 degrees Fahrenheit.
- More information on controlling Legionella growth in cooling towers can be found on CDC’s controlling Legionella in cooling towers website.