# 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. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://guidelines.nhmrc.gov.au/australian-drinking-water-guidelines/part-1/chapter-3/3.2-assessment-of-the-drinking-water-supply-system-element-2/3.2.2-assessment-of-water-quality-data.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.