9.4 Operational monitoring

Preventive measures and barriers to contamination should be applied from catchment to consumer in accordance with the multiple barrier approach, and these measures and barriers should be regularly monitored to assure their ongoing effectiveness.

Operational monitoring includes a planned sequence of measurements and observation throughout the water supply system to ensure and confirm performance of preventive measures and barriers to contamination. The importance of operational monitoring to the effective maintenance of preventive barriers to contamination cannot be overstated. To be effective, operational monitoring is needed at those points within the water supply system, including critical control points (see Box 9.4), such that if an adverse result is obtained, corrective action can be triggered to ensure that unsafe water does not reach the consumer.

Developing a protocol for monitoring operational performance of a water system requires the following steps:

• Identify preventive measures (see Element 3 of the Framework, Section 3.3).

• Select operational characteristics and associated operational criteria (objectives) to be used to assess the operational process or activity.

• Establish corrective actions to address any excursions in operational characteristics from defined criteria/objectives.

• Include frequent, routine monitoring of operational characteristics and ongoing analysis of monitoring results.

Box 9.4

Critical control points

A critical control point (CCP) is defined as an activity, procedure or process at which control can be applied, and that is essential to prevent a hazard or reduce it to an acceptable level.

For each CCP, a critical limit for operational performance needs to be established that represents a complete loss of control of the process and the existence of an unacceptable health risk. Failure to meet a critical limit should result in immediate notification of the relevant health authority or drinking water regulator.

To be effective, and to provide assurance that unsafe water is not delivered to consumers:

• Those characteristics that are monitored at CCPs should be monitored continuously, using on-line analysers wherever possible.

• The monitoring should be alarmed so that operational staff are alerted promptly of adverse results.

Wherever possible, data should be sent to a supervisory control and data acquisition (SCADA) system (or some equivalent data capture system), so that trends over time can be evaluated and acted upon.