Magazine
Water Hygiene on ships: challenges & international standards
Providing flawless drinking water on ships of all sizes is often a logistical and technical challenge for ship owners or fleet operators – and on passenger ships, it is simultaneously a clear expectation of the guests.
Water hygiene challenges on ships
The (long) piping systems, fluctuating extraction volumes and changing water sources in (international) ports are the greatest challenges for ships of all sizes.
| Small ships & yachts | Large ships (Freight/Navy) | Cruise ships | |
|---|---|---|---|
| Main risk | Rapid heating of the pipes, especially in warm waters. | Lack of flow: Long periods at berth in ports or unused sections. | Complexity: Enormous distribution networks with thousands of extraction points. |
| Piping systems | Short, but often in hot environments (engine room/hull). | Functional, often long spur lines to the cabins. | Often very branched; risk of dead legs and biofilm formation tends to be high. |
| Water source | Often own production (desalination) or small quantities of shore water. | Large bunker quantities, intake in changing ports worldwide. | Mix of desalination and bunkering; highest requirements for treatment. |
| User group | Owners, small crew, few guests. | Experienced crew, mostly healthy adults. | Very heterogeneous, often seniors, some guests with pre-existing conditions. |
The different challenges on the various types of ships, particularly the combination of stagnation and warm temperatures, favour the formation of biofilm, which provides ideal conditions for the growth of pathogens such as Legionella pneumophila or other waterborne bacteria and germs.
Accordingly, it is important on ships to ensure flawless drinking water hygiene.
The “Guide to Ship Sanitation” by the World Health Organization (WHO) is the overarching standard work for hygiene on ships in this context, in order to prevent the spread of diseases.
Water hygiene on smaller ships without crew
For smaller ships and yachts, it is recommended to rely on compact water filters, such as the AS FILL Season, already during the bunkering process in order to reliably prevent the entry of pathogens into your tanks.
In addition, inline systems or point-of-use filters at the extraction points provide a secure barrier that filters bacteria out of the water immediately before contact with the user.
Water hygiene on larger ships with crew
The Maritime Labour Convention (MLC) of the International Labour Organization (ILO) sets binding minimum standards for living and working conditions on board, which include drinking water hygiene.
Core points of drinking water hygiene are:
- Ensuring drinking water quality: The MLC obliges shipowners and captains to provide drinking water of suitable quality, quantity and sufficient nutritional value.
- Health protection: The drinking water must be safe enough to drink. The convention defines regulations that guarantee high quality standards for drinking water on board in order to protect the health of seafarers.
Water hygiene on cruise ships
On a cruise ship, two worlds collide: A highly complex, mobile water system – often with hot water areas and aerosol formation – and the guests' expectation of a carefree holiday.
A single incident here can not only endanger the health of passengers but also damage the reputation of the entire shipping company.
In order to be able to operate flexibly worldwide while simultaneously ensuring the highest safety standards, a hybrid strategy has proven successful in many parts of the industry.
1. CDC-VSP: The technical benchmark for cruise ships
The Vessel Sanitation Program (VSP) of the Centers for Disease Control and Prevention (CDC) sets the technical benchmark for cruise ships with regard to drinking water hygiene.
The CDC, an agency of the US Department of Health and Human Services, defines hygiene protection for cruise ships calling at US ports or embarking passengers in the USA. And since almost all major shipping companies serve these routes, the standards have a global impact and effectively shape the global benchmark for water hygiene on cruise ships.
In the latest version of the CDC-VSP standards, a significant expansion now includes, for the first time, mandatory Legionella monitoring as well as stricter documentation and monitoring rules in the regulations, which close formal gaps in many areas. Learn more about the specific CDC-VSP standards 2025 here.
2. European Manual: The operational framework in Europe
While the technology is often installed based on the US model according to CDC-VSP, many operators in European waters use the European Manual for Hygiene Standards and Communicable Disease Surveillance as a guideline for daily operations. It provides a comprehensive framework for daily health management and the monitoring of infection risks by relying on continuous risk analysis that goes beyond pure technology and also incorporates crew behaviour and on-board processes.
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How Aqua free supports shipping companies
Aqua free has been supporting shipping companies for many years in the hygiene protection of water-bearing systems.
Our solutions facilitate implementation:
- Retention of bacteria through 0.2 µm hollow fibre membranes
- Cabin and shower filters for guest and crew areas
- Solutions for spa installations and areas with aerosol formation
- Support with risk assessment, planning and operation
- Products that crews can deploy quickly and handle safely
Do you have any questions? Please feel free to contact us!