Onboard water contamination: A hidden risk you can’t afford to ignore

Maintaining impeccable water hygiene on board vessels is paramount to safeguarding the health of both passengers and crew. Neglecting this critical aspect can lead to severe health risks, including outbreaks of diseases such as Legionnaires’ disease, E. coli infections, MRSA, and norovirus.

These incidents not only jeopardise individual well-being but can also damage a vessel’s reputation and result in significant operational disruptions.

Dirty water. Serious consequences

Recent incidents highlight the pressing nature of water hygiene in maritime environments. Over 50 incidents of Legionnaires’ disease, involving more than 200 cases, have been associated with ships in the past three decades. In one incident, 50 seafarers were infected, resulting in one death.

Between November 2022 and June 2024, two cruise ships reported Legionnaires’ disease outbreaks, with 12 passengers affected. The source was traced to outdoor hot tubs on private cabin balconies.

More recently, in November 2024, the Coral Princess experienced a norovirus outbreak during a Singapore to Los Angeles voyage, affecting 70 individuals and demonstrating how rapidly water-borne pathogens can spread in maritime settings.

These are the four primary health risks that maritime operators must vigilantly guard against:

Legionnaires’ disease

Caused by the bacterium Legionella pneumophila, this severe form of pneumonia thrives in freshwater environments, particularly in man-made water systems like those found on ships. Inadequate maintenance of water systems can lead to the proliferation of these bacteria, posing a significant health risk.

E.coli infections

Escherichia coli bacteria are commonly found in the intestines of humans and animals. Certain strains can cause severe gastrointestinal illness if ingested through contaminated water or food. On vessels, improper sewage handling or contaminated potable water supplies can facilitate the spread of E. coli.

MRSA

Methicillin-Resistant Staphylococcus aureus is an antibiotic-resistant bacterium can cause various infections, from skin conditions to more severe diseases. While MRSA is often associated with direct contact transmission, contaminated water sources can also play a role in its spread, especially in communal areas like pools or spas.

Norovirus

Highly contagious, norovirus leads to acute gastroenteritis, causing symptoms like vomiting and diarrhoea. It can spread rapidly in confined environments such as ships, particularly through contaminated water or surfaces.

Preventative measures and best practices: keeping water clean onboard

To mitigate these risks, those responsible for onboard health and safety should implement comprehensive water hygiene management plans:

Regular monitoring and maintenance

Conduct routine inspections of all water systems, including potable water supplies, swimming pools, spas, and HVAC systems. Regular testing for pathogens like Legionella and E. coli is essential.

Water treatment protocols

Ensure appropriate disinfection methods are in place, such as stabilised hydrogen peroxide treatment, chlorination or ultraviolet (UV) treatment, to maintain water quality. Choosing the right disinfection method requires careful evaluation of multiple factors.

The method must eliminate pathogens but also be capable of effectively penetrating and eliminating biofilms – protective layers where dangerous pathogens can hide.

However, it’s equally important to consider potential drawbacks, including long term corrosive effects on equipment, whether neutralisation will be necessary, and the risk of creating harmful disinfection byproducts or exposure to toxic gasses.

Crew training

Educate crew members on the importance of water hygiene and train them in proper maintenance procedures and emergency response actions in case of contamination.

Passenger awareness

Inform passengers about the importance of personal hygiene, such as regular handwashing, and provide guidance on safe water consumption practices while on board.

Emergency response plans

Develop and rehearse response plans for potential outbreaks, including isolation procedures, communication strategies, and coordination with health authorities.

Comprehensive onboard water hygiene management

The hazards associated with failing to maintain water hygiene on board vessels are significant, with the potential for severe health consequences and operational disruptions.

By implementing rigorous water hygiene management practices, vessel operators can protect the well-being of passengers and crew, uphold their reputation, and ensure smooth sailing operations.

EndoSan: advanced water treatment solution for vessels

EndoSan is an ultra-stabilised hydrogen peroxide-based biocide, commonly used on board vessels for water treatment applications. It is highly effective for disinfecting and maintaining hygiene in various water systems, environmentally-friendly (biodegrades into water and oxygen), and offers protection against broad-spectrum antimicrobial activity. Here are its key uses:

Potable water treatment

• Disinfects drinking water systems to ensure safe, pathogen-free water for crew and passengers.
• Prevents bacterial growth, including Legionella, which can thrive in warm water systems.

Cooling systems & HVAC

Treats cooling towers and HVAC systems to prevent biofilm formation and microbial contamination.

Grey & black water systems

Helps maintain hygiene in wastewater systems by controlling odour-causing bacteria and pathogens.

Surface disinfection

Used as a surface sanitiser in areas like kitchens, galleys, and food preparation zones to maintain hygiene.

In addition to EndoSan, we offer a complete portfolio of solutions to manage water quality and hygiene across all onboard systems, equiping marine operators with everything they need to maintain safety, compliance, and system efficiency, and safety.

Contact us today to find out how we can help with your vessel’s water quality management.