Preventing Recreational Water Illnesses – What Needs Attention

Preventing recreational water illnesses in hotels and other venues is crucial for public safety.


A hotel pool can be a prime attraction for families on vacation. Still, with hundreds of thousands of people using these pools yearly, recreational water illnesses (RWI) pose a considerable risk. 

Cryptosporidium, legionella, and pseudomonas are dangerous organisms lurking in seemingly clean and chlorinated pool water. These lead to painful symptoms and even hospitalization. In this article, we’ll present the dangers of RWI and how to keep yourself and your family safe.

The Dangers of RWI

Between 2000 and 2014, 493 cases of RWI were reported in the United States, leading to 27,219 individual illnesses and eight deaths. Unfortunately, hotels were responsible for 157 (32%) of these cases, with the most common culprit being cryptosporidium, a gastrointestinal illness-causing parasite. Legionella, which causes severe pneumonia, was followed by pseudomonas, which causes swimmer’s ear and hot tub rash.

disinfect swimming pool

Aquatic Venues at Risk

Hotels are just some of the venues facing this problem. Community pools, school pools, private pools, and any aquatic facility can be a breeding ground for these harmful organisms. The warmer months of June, July, and August typically see the highest number of hotel outbreaks. Still, with the rise of indoor aquatic facilities, RWI outbreaks are expected to become a year-round concern.

Pool water is generally treated with chlorine to prevent the spread of RWI. However, cryptosporidium is highly resistant to chlorine, making it difficult to eliminate. The Centers for Disease Control and Prevention (CDC) recommends a minimum concentration of 1 ppm of free chlorine to inactivate most pathogens. Still, cryptosporidium can survive for over a week in water, leading to outbreaks that can spread to multiple venues and make thousands of people sick.

While legionella and pseudomonas are not as resistant to chlorine, the correct concentrations of disinfectants must be used in the water treatment. A 2013 study found that 20% of aquatic venues needed to adjust the disinfectant levels.

Preventing RWI Outbreaks

Public aquatic venues’ design, construction, operation, and management must be improved to prevent RWI outbreaks. A step in the right direction for ensuring the safety of public pools and spas is to adopt the Model Aquatic Health Code (MAHC). The public also plays a role in preventing RWI by avoiding swimming or using public aquatic facilities if they have diarrhea or if their children have recently suffered from it.

The CDC recommends hyper-chlorinating the water to achieve a 3-log cryptosporidium inactivation if a diarrhea incident occurs. Ultraviolet disinfection and ozone equipment are also effective in eliminating these harmful organisms. Ultraviolet technology is an approved secondary disinfectant in the MAHC. It is efficient for use in aquatic venues used by children under five years old, where the risk of contamination is high.

While UV technology can inactivate harmful organisms immediately, these systems must be designed in such a way as to ensure maximum exposure to ultraviolet light. With UV systems, pool water can be effectively disinfected without relying on high chlorine levels; the risk of RWI outbreaks is thus reduced, and the swimming experience becomes more enjoyable and safe.



Preventing RWI outbreaks at hotels and other aquatic venues is crucial to ensure public safety. Implementing the Model Aquatic Health Code (MAHC) can help drive improvements in the design, construction, operation, and management of public aquatic venues. Ultraviolet technology is an efficient solution when the system is designed and specified in such a way as to maximize exposure to UV light.

The public also plays a vital role in ensuring aquatic venues remain safe. Avoid swimming and visiting public aquatic facilities if you or your children experience symptoms of diarrhea until fully recovered. Regular hyperchlorination and disinfectant monitoring can also help reduce the risk of RWI outbreaks.

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Date 09/08/2023


Nuvonic is the innovator in sustainable UV technology for water, air and surface disinfection on a global scale. Our mission is to support nature’s purity with science by protecting people and processes from harmful contamination.

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