Decision support tool

Water Safety Plan

The 2004 revision of the WHO Guidelines for Drinking-water Quality follows a profoundly different approach for ensuring drinking-water safety. They emphasize that focusing on compliance to guideline values or standards in finished water is not sufficient to ensure safety. Rather, safety is attained through stringent process control from catchment to consumer. The new paradigm of a systematic approach to this is the Water Safety Framework, of which Water Safety Plans (WSP) are a central element.

The WSP concept focuses attention on risk assessment and on process control. It is an operational system of quality management. This structured, systematic approach to process control is particularly useful for managing cyanotoxin risks. For a detailed instruction see the WSP manual by WHO.

The performance of a WSP contains the following steps:

  1. System description
    Description of the whole supply chain from catchment to consumer, or from the catchment to the bathers for recreational use.
  2. System assessment: hazard analysis and risk assessment
    Identification and analysis of the hazards which may potentially occur, as well as their causes or causative circumstances. The risk assessment analyses the severity – in combination with the probability – of a risk and also helps to rank the different risks relative to each other.
  3. Risk management
    All existing management and technical control measures are evaluated for their suitability to control the hazards identified (validation). Also the operational monitoring and the correction actions are evaluated and eventually other control measures are implemented.
  4. Confirmation of the drinking water quality (verification)
    Herewith, it is proven that, with the control measures in place, the aim to ensure safe drinking water (i.e. meeting the standards) is met.

Steps 1-4 need to be documented (documentation) and to be revised (revision) at regular intervals, or when substantial parts of the supply chain are changed.

Different stakeholders are usually affected when establishing a WSP, which often leads to conflicts. A successful implementation of a WSP is more likely if all stakeholders are involved in the decisions about quality targets and control measures.