Does drinking water transmit Legionnaires' disease?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Drinking water does not directly cause Legionnaires' disease. The bacteria responsible, Legionella, spreads when contaminated water becomes aerosolized—through mist, steam, or vapor from showers, hot tubs, humidifiers, or cooling systems—and is inhaled into the lungs. Swallowing water is not the typical route of infection; the risk comes from breathing in tiny water droplets containing the bacteria.

Symptoms of Legionnaires' disease can mimic pneumonia and include fever, cough, shortness of breath, muscle aches, and headaches. Because these signs overlap with many other illnesses, it can be difficult to know whether your symptoms are serious or benign. Rather than guessing—or waiting until things worsen—it's smart to get clarity now. Take a free, instant, online symptom check to better understand what may be causing your symptoms and confidently plan your next steps.

Reviewed for medical accuracy: 07/20/2026

Important Next Steps

Learn if your symptoms need care today Discover likely causes of fever and cough See if it could be Legionnaires’ disease Find OTC relief for fever and cough Find a doctor for infectious diseases Discover safe home remedies for symptoms Understand if these symptoms need urgent care

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Explanation

Legionnaires' disease is caused by bacteria called Legionella, which can grow in water systems like plumbing and air conditioning systems. While drinking water itself does not directly cause the disease, the bacteria can thrive in warm water environments and become a risk if the water is turned into mist or vapor, such as in showers or hot tubs.

How It Spreads:

Water Systems: Legionella bacteria can grow in large water systems, especially if the water is not properly maintained.
Inhalation: People can get sick by breathing in water droplets containing the bacteria. This can happen in places like showers, fountains, or air conditioning systems.

Prevention:

Regular maintenance and cleaning of water systems can help prevent the growth of Legionella.
Ensuring water temperatures are kept outside the range where the bacteria thrive (77°F to 113°F) can also reduce risk.

In summary, while drinking water is not the direct cause of Legionnaires' disease, proper maintenance of water systems is crucial to prevent the spread of Legionella bacteria. If you're experiencing respiratory symptoms and are concerned about possible exposure, take a free symptom checker test to better understand your condition.

(References)

Gleason JA, & Cohn PD. (2022). A review of legionnaires' disease and public water systems. International journal of hygiene and environmental health, 34923288.
Mapili K, Pieper KJ, Dai D, Pruden A, Edwards MA, Tang M, & Rhoads WJ. (2020). Legionella pneumophila occurrence in drinking water .... Letters in applied microbiology, 31904109.
Dufresne SF, Locas MC, Duchesne A, Restieri C, Ismaïl J, Lefebvre B, et al. (2012). Sporadic Legionnaires' disease: the role of domestic .... Epidemiology and infection, 21396146.

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