Published: April 21, 2026 | Source: Alabama Department of Public Health

In 2023, health officials in Grand Rapids, Minnesota, investigated an outbreak of Legionnaires' disease that affected 34 people. Thirty required hospitalization, and two lives were lost. After a thorough investigation, officials determined that the municipal water system was the common source of exposure. In response, a chlorine disinfection system was installed at the public water supply in June 2024. Since then, no new cases have been reported.

This incident highlights an important public health concern that affects communities nationwide. Understanding Legionnaires' disease—and how to prevent it—helps protect you and your loved ones.

What Is Legionella?

Legionella is a type of bacteria naturally found in freshwater sources like lakes and streams around the world. On its own, it usually does not cause harm. Problems arise when the bacteria grow and spread in human-made water systems.

Legionella thrives in conditions such as:

Water temperatures between 77°F and 108°F
Stagnant or rarely used water lines
Buildup of sediment, scale, or biofilm inside pipes and fixtures
Low or absent levels of disinfectant like chlorine

These conditions can occur in large buildings, hotels, hospitals, hot tubs, decorative fountains, and even home plumbing systems if not properly maintained.

What Is Legionnaires' Disease?

Legionnaires' disease is a serious form of pneumonia caused by inhaling tiny water droplets that contain Legionella bacteria. These droplets can come from showers, hot tubs, misting devices, cooling towers, or faucets.

Important to know: Legionnaires' disease does not spread from person to person. You cannot catch it by being near someone who is sick.

Recognizing the Symptoms

Symptoms usually appear 2 to 10 days after exposure and may include:

Cough (sometimes with mucus or blood)
Fever and chills
Headache
Muscle aches
Shortness of breath or difficulty breathing

Because these symptoms resemble other types of pneumonia, it is important to see a healthcare provider promptly if you feel ill—especially if you have recent exposure risks.

Who Is at Higher Risk?

While anyone can develop Legionnaires' disease, certain groups face greater risk:

Adults over age 50
Current or former smokers
People with chronic lung conditions like COPD or emphysema
Individuals with weakened immune systems due to illness or medication
Those with underlying conditions such as kidney disease, liver disease, or cancer

If you develop pneumonia-like symptoms and have recently used a hot tub, stayed overnight away from home, or been in a hospital or long-term care facility, tell your doctor. Mentioning possible Legionella exposure helps ensure faster, more accurate treatment.

Treatment and Outlook

Legionnaires' disease is treated with antibiotics. Because it can be severe, many patients require hospitalization. With timely care, most people recover. However, about 1 in 10 cases can be fatal, especially when diagnosis or treatment is delayed.

How to Reduce Your Risk

The best protection against Legionnaires' disease is proper maintenance of water systems. Whether you manage a building or maintain your own home, these steps help keep water safe:

Keep hot water hot (at least 120°F) and cold water cold (below 68°F) to discourage bacterial growth
Flush rarely used faucets, showers, or fixtures regularly to prevent stagnation
Clean and disinfect showerheads and faucet aerators periodically
Maintain proper chlorine or other disinfectant levels in pools, hot tubs, and decorative water features
Follow manufacturer instructions for cleaning and maintaining humidifiers, misters, and other water-using devices

For building owners and facility managers, the Centers for Disease Control and Prevention offers a free toolkit: "Developing a Legionella Water Management Program." This resource aligns with industry standards and helps create a proactive plan to monitor and control Legionella risk.

Healthcare facilities, nursing homes, and other high-risk settings should also consult specialized guidance. For example, the University of Alabama at Birmingham's Alabama Regional Center for Infection Prevention & Control recently hosted a webinar on Legionella prevention tailored to long-term care facilities.

Stay Informed, Stay Protected

Legionnaires' disease is preventable. By understanding how the bacteria spread and taking simple steps to maintain water systems, communities and individuals can significantly reduce risk.

If you have concerns about your home water system, building maintenance, or personal health risks, talk to your healthcare provider or contact your local health department.

This article is provided by Crestwood General. For more health resources and community wellness information, visit crestwoodgeneral.com