3.2.2 Assessment of water quality data

Summary of actions

• Assemble historical data from source waters, treatment plants and finished water supplied to consumers (over time and following specific events).

• List and examine exceedances.

• Assess data using tools such as control charts and trends analysis to identify trends and potential problems.

A review of historical water quality data can assist in understanding source water characteristics and system performance both over time and following specific events such as heavy rainfall. This can help in identifying hazards and aspects of the drinking water system that need improvement.

Where available, water quality data should be assessed from monitoring of source waters, the operation of treatment processes, and drinking water as supplied to consumers. Trends analysis and control charts can be valuable tools for recognising potential problems or hazards and the accumulation of any gradual changes or cumulative effects.

Further information is provided in Section 10.3 and Information Sheet 3.2.