A Perth water report answers a more useful question once you have matched its reporting area to your address. Start with the water-quality locality, then keep the sampling period beside each result. A figure for a regional network cannot tell you what was measured at one household.
Match the reporting area to the address
Water Corporation's annual report describes the Perth Metropolitan Region as extending from Two Rocks to Dwellingup and from the ocean to the Darling Scarp. It divides the interconnected supply into 27 water-quality localities, with independent Two Rocks counted as a further locality. Those are the management areas used in this report. Read the regional description on page 16 of the 2024-25 annual report.
The linked locality maps have north, central and south sheets, a printed date of 4/12/2020 and a scale of 1:350,000 at A4. These are broad water-quality boundary maps. The colours locate named areas; they do not show a tested kitchen tap. Open the original locality maps at a readable size. If a property sits near a boundary or its suburb name differs from the table label, ask Water Corporation to confirm the relevant locality.
The integrated scheme reaches beyond Perth
The Integrated Water Supply Scheme also serves Peel, Goldfields and Agricultural areas, parts of the South West and the Upper Great Southern. Its facilities include groundwater treatment, desalination, groundwater replenishment and dams. The scheme overview explains that larger network.
That geography is useful when a search result mentions the IWSS. Check whether a sentence describes the whole scheme, the Perth region or one locality before applying it to your accommodation. A network description establishes which sources and facilities belong to the system; it leaves the current blend at a particular tap unresolved. We have not matched a Perth address to a locality or obtained its current source proportions.
Read the period and footnotes
The annual report reviews the financial year ending 30 June 2025. Its Perth health tables explicitly cover 1 July 2024 to 30 June 2025. Reading the files in October 2026 does not move their measurements into that month.
The health-related tables separate sample counts from results and guideline or requirement indicators. Some concentration columns have minimum, maximum and mean values. Their footnote explains that certain zero sample counts mean no samples were required during that period. A blank or zero sample count therefore needs its footnote before you decide what it says about testing.
For a parameter you are investigating, copy its complete row heading, unit and statistic. Keep the locality name and period with it. A mean answers a different question from a maximum, while a sample count describes the monitoring behind the row. None is a new sample from your property.
Find the right file again
Water Corporation's drinking-water-quality index links annual reports, regional health and aesthetic tables, and locality maps separately. Return to that index when looking for a newer report rather than relying on a saved search snippet.
Keep a copy of the file you used and note the date you accessed it. Our Perth guide addresses the broader traveller question. The Lisbon report-reading article gives another example of checking sampling scope, using a different utility's records. For a Perth property question, take the exact address and parameter back to Water Corporation.
