Sunbury Water Hardness & Quality Report (2026)

Sunbury's drinking water is supplied by Western Water, drawing on a blended supply incorporating the Goldfields Superpipe interconnection, Rosslynne Reservoir on the Maribyrnong River, and connections to the Coliban and Campaspe system in the outer north Melbourne and central Victorian interface in Victoria. Water hardness in Sunbury is measured at 81.5 mg/L — classified as slightly hard — within the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. Western Water's blended supply system serves the Macedon Ranges and outer north Melbourne growth corridor including Sunbury.

Sunbury's slightly harder supply reflects Western Water's blended supply character. The Rosslynne Reservoir catchment on the Maribyrnong River and the Goldfields Superpipe connections draw on water from a mix of sources — including central Victorian catchments that drain through Devonian granodiorite and Ordovician–Silurian sedimentary goldfields terrain. The goldfields sedimentary component contributes measurably more calcium and magnesium than the pure Yarra Ranges granite-sourced supply, producing the 81.5 mg/L hardness at the Sunbury outer suburban tap.

Sunbury residents see occasional moderate limescale deposits on taps and in kettles — descaling every two to three months is typically adequate. Hot water systems benefit from periodic inspection to check for scale accumulation. The elevated lead reading (0.004 mg/L) warrants applying the ADWG precautionary guidance of briefly running the cold tap before use in older homes in Sunbury's established heritage residential streets. Western Water provides water quality information at westernwater.com.au, with all ADWG health standards consistently met throughout the Sunbury distribution network.