Legionnaires’ Disease on Cruise Ships: Risks From Hot Tubs, Pools, and Bathtubs

A Hidden Health Risk at Sea

Cruise ships offer pools, whirlpools, private balcony hot tubs, spas, and in-cabin bathing facilities intended to help passengers relax. However, these amenities can become a source of serious illness when contaminated water allows Legionella bacteria to grow and spread.

Legionella can cause Legionnaires’ disease, a severe form of pneumonia, as well as Pontiac fever, a generally milder illness. People typically become infected by breathing in mist or small water droplets containing the bacteria. Legionnaires’ disease generally does not spread from one person to another.

Cruise ships contain extensive, interconnected water systems serving thousands of passengers and crew members. Without appropriate temperature control, disinfectant levels, circulation, cleaning, and testing, parts of these systems may create conditions in which bacteria can multiply.

How Cruise Ship Hot Tubs and Pools Can Spread Legionella

Hot tubs and whirlpools present a particular concern because their warm water can support bacterial growth while their jets release mist into the surrounding air. A passenger may therefore be exposed even without fully entering the water.

Pools, splash features, faucets, showerheads, jetted bathtubs, and other fixtures may also create exposure when contaminated water is sprayed or aerosolized. Possible maintenance failures may include:

• Inadequate chlorine, bromine, or other disinfectant levels
• Failure to monitor the water’s pH
• Water temperatures that encourage bacterial growth
• Poor filtration or circulation
• Biofilm, scale, sediment, or corrosion inside equipment
• Failure to drain and clean tubs regularly
• Incomplete maintenance or inspection records
• Failure to close an amenity after signs of contamination
• Improper treatment of the ship’s broader potable water system

CDC inspectors review cruise ship swimming pools and whirlpools by examining operating logs, sampling water, and checking whether disinfectant and pH levels meet applicable public health standards.

Legionnaires’ Outbreaks Have Occurred on Cruise Ships

The threat is not merely theoretical. In an investigation covering November 2022 through June 2024, the CDC identified 12 cases of Legionnaires’ disease among travelers on two cruise ships. Investigators determined that private balcony hot tubs were the likely sources of exposure.

Some of the hot tubs had reportedly operated for extended periods without residual disinfectant while maintaining water within a temperature range favorable to Legionella growth. The investigation also noted that contaminated mist from private hot tubs could potentially reach nearby common areas, exposing people who never used the tubs themselves.

These findings demonstrate why cruise lines must carefully maintain both public amenities and water features provided for private passenger use. This is only one of many outbreaks that occur on cruise ships.

Symptoms Passengers Should Take Seriously

Symptoms of Legionnaires’ disease often resemble other types of pneumonia and may include:

• Cough
• Shortness of breath
• Fever or chills
• Headache
• Muscle aches
• Nausea, vomiting, or diarrhea
• Confusion

Symptoms usually develop within two to 14 days after exposure, although they can occasionally appear later. Adults age 50 and older, current or former smokers, people with chronic lung disease, and those with weakened immune systems may face a greater risk of becoming seriously ill. Some people may develop milder symptoms that are typically diagnosed as Pontiac fever. 

Anyone experiencing these symptoms after using a cruise ship hot tub, pool, spa, or bathing facility should seek medical care promptly. Passengers should specifically mention their cruise dates and any water amenities they used, since Legionnaires’ disease cannot be reliably distinguished from other causes of pneumonia based only on symptoms or imaging.

What to Do After a Suspected Cruise Ship Exposure

Passengers who believe they contracted Legionnaires’ disease on a cruise should preserve information that may help identify the source of exposure. Helpful evidence may include:

• Medical records and laboratory test results
• Cruise tickets and booking confirmations
• The vessel’s name and sailing dates
• Photographs or videos of pools, spas, or private hot tubs
• Receipts for onboard spa services
• Names of travel companions or other sick passengers
• Communications with the cruise line
• A written timeline of water-related activities and symptoms
• Copies of illness or incident reports submitted onboard
• A list of other passengers who had similar symptoms

A maritime attorney may seek additional evidence from the cruise line, including water-testing results, maintenance records, inspection findings, cleaning schedules, prior complaints, and reports of similar illnesses.

When a Cruise Line May Be Responsible

A cruise line may be liable when it knew or should have known that a water system presented an unsafe condition but failed to correct it, warn passengers, or follow reasonable maintenance and sanitation practices.

Potential compensation may include medical expenses, lost income, pain and suffering, rehabilitation costs, and other losses. Families who lose a loved one may also have grounds to pursue a wrongful death claim.

Cruise passenger claims may be governed by maritime law and the terms of the passenger ticket contract. Because these cases can involve strict notice and filing deadlines, it is important to speak with an attorney as soon as possible.

Morgan & Morgan Is Here to Help

Legionnaires’ disease can result in hospitalization, substantial medical bills, missed work, and lasting health complications. Passengers should be able to enjoy cruise ship pools, hot tubs, and bathing facilities without being exposed to preventable health hazards.

Morgan & Morgan’s maritime accident attorneys can investigate the ship’s maintenance practices, preserve important records, identify potentially responsible parties, and fight for the compensation you may deserve.

Contact Morgan & Morgan today for a free, no-obligation case evaluation. With the Fee Is Free™, you pay nothing unless we win your case.