Recent high-profile cases of contamination on cruise ships have highlighted the importance of water safety. But it is an issue that has important implications across the merchant fleet too. Michael Hagger, environmental and public health consultant at RenovaTech International, explains how an effective water safety plan can prevent the costly occurrence of waterborne illness among passengers and crew.

Using the World Health Organisation’s (WHO) Guide to Ship Sanitation, which replace the old De–Ratting Certificate and have a much wider scope, including recommendations for ships to implement water safety plans. Further, it has been reported that in some European ports health authorities are using the Shipsan Manual Guidelines as a base for their health and sanitation inspections.

The use of advanced technologies for water treatment such as membrane filtration, disinfection and re–mineralization, coupled with a variety of sea–water desalination processes, make water systems in the marine industry some of the most complex. Modern ships’ fresh water systems must be designed to take into account several factors:

  • The variable quality of water available in ports for bunkering;
  • The production of fresh water on board by desalination;
  • Storage capacity (within the confines of vessel stability and cargo carrying);
  • Distribution systems to overcome space restrictions;
  • The proximity of potable water and other non–potable services; and
  • Corrosion and scaling in pipe–work due to different materials/water chemistry.

WHO guidelines for drinking water quality introduced in 2004 introduced the water safety plan (WaSP) approach, describing it as “the most effective means of consistently ensuring the safety of drinking water”. WHO’s 2011 Guide to Ship Sanitation and 2007 Guidelines for Prevention of Legionellosis also suggest the use of WaSPs on ships.

More recently, in October 2011 the European Commission Directorate General for Health and Consumers issued the European Manual for Hygiene Standards and Communicable Disease Surveillance on Passenger Ships, commonly known as the Shipsan Manual. This manual. produced with the co–operation of the cruise industry, advocates the use of WaSPs and draws parallels with the use of Hazard Analysis and Critical Control Point (HACCP) for the management of food safety – a system already well established with most shipping companies and often integrated into the company’s overall safety management system (SMS).


The complexity of the water systems makes the application of a risk management process more difficult but even more important in ensuring that all potential hazards to health have been removed or lowered to an acceptable level. Risk management is the collective term used for the process of identification of hazards and hazardous events, deciding who will be harmed and how, evaluating the risks and determining what precautions must be taken, recording findings and implementing precautionary measures, and finally reviewing the assessment and updating it if necessary.

Water management on ships may already meet legislative requirements and adequately provide safe drinking water without a WaSP. But the management and control measures that have been put in place may not include hazard identification and risk assessment or be tailored for each specific system. A WaSP is essentially a framework of hazard identification, risk assessment and risk management including the control measures, monitoring, incident and emergency plans, and the associated documentation for each stage in the provision of safe water from loading to the point of delivery to the user.

A WaSP has three key components:


A system assessment to determine whether the water system as a whole can deliver water of a quality that meets health-based targets. This assessment identifies the potential hazards in each part of the drinking water system and the level of risk presented by each identified hazard. It also includes the appropriate measures to ensure that water is safe for use, that standards and targets are met and that human health is protected.

Operational monitoring of an appropriate nature and frequency at an appropriate point in the water system is defined for each control measure identified and implemented from the system assessment. This ensures that any deviation from the required performance is rapidly detected.

Documentation of management arrangements includes details of the system assessment, operational monitoring and validation monitoring. Also included is a description of actions to be taken in normal operation, or when there is a risk of non–compliance with a standard or target value, a failure to meet an operational control or a potential risk to human health. These actions should include appropriate investigations, remedial action in the form of improvement programmes, reporting and communication.

These components require a thorough understanding of each element of the specific water supply chain and its capability to supply water that is safe and meets the health based standards. Targets for indicator parameters and other requirements aimed at protecting human health must be set.

Hazards for each element of the water supply chain – the potential sources of contamination, whether they present a risk for that element of the water supply chain and an estimate of that risk – must also be identified. So too must the control measures for each risk.

A system of routine monitoring of those control measures must be implemented. with criteria for triggering action when the control measures are not within the specified targets. A plan of remedial action is also needed for when a control measure is not within the specified target, including checking that the action has brought the system back under control.

Validation monitoring should be implemented to determine whether the system is performing as assumed in the system assessment. Finally, verification by an independent body is recommended to ensure that the WaSP is being implemented correctly and is ensuring that the water supplied is safe and meets health–based and other regulatory targets.

A periodic audit of the WaSP is required. In addition to a review of documentation, the audit should ensure the following:

  • Operational parameters within specification;
  • Verification steps provide a reliable overview of WaSP performance;
  • The WaSP is being reviewed and updated on a regular basis;
  • Training programmes are being followed.

The use of regular external auditing provides a good opportunity not only for the WaSP to be assessed by an experienced marine water management practitioner, but also for ‘a fresh pair of eyes’ to look for potential hazards that previously may not have been considered.

Consider this statement from the operator of one large container vessel: “We don’t have any problem on this ship because we drink bottled water and produce all our own fresh water by desalination. We never bunker water.”

An independent audit of the ship’s WaSP showed however that several risks had not been adequately minimised. A lack of disinfection in storage tanks had left stored water unprotected from growth of microorganisms. Low-temperature evaporation (vacuum distillation at <80°C) used for desalination had not been followed by disinfection to provide a residual effect. Legionella was also found in the water system, and although the risks arising from drinking contaminated water had been addressed, the risk of legionella bacteria growing in the system had not been tackled.


In general, there was evidence of inadequate commissioning procedures of the water system on the new build ship, which was probably responsible for initial contamination of the water system. The conclusion is clear: If you don’t commission water systems properly, you may have lost control forever.

The WaSP thus provides a systematic, detailed and prioritised assessment of actual and potential hazards. It ensures operational monitoring of control measures and provides an organised and structured system to minimise the likelihood of failures. This dynamic approach can lead to future improvements in the water supply management, and assists competent authorities in conducting inspections.

It is looking likely that the implementation of WaSPs will be the required standard in the not too distant future. European and other major port health authorities across the world will look for them when they carry out inspections for the issuance of Ship Sanitation Compliance Certificates or Ship Sanitation Exemption Certificates. For companies investing the time and effort in implementing a WaSP though, the biggest reward will be safer and more efficient operations.