Reservoir Water Hardness & Quality Report (2026)

Reservoir's drinking water is supplied by Yarra Valley Water as water retailer, with bulk supply from Melbourne Water drawn from the Thomson Reservoir and Upper Yarra Reservoir catchments in the Yarra Ranges, Victoria. Water hardness in Reservoir (Darebin LGA) is measured at 21 mg/L — classified as very soft — far below the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. The suburb takes its name from the former Preston Reservoir, which historically served as a key storage point in Melbourne's north-central distribution network before the modern integrated system was established.

Reservoir's very soft supply traces directly to the catchment geology of the Yarra Ranges. The Thomson and Upper Yarra storages collect water draining across Devonian granite and metamorphic rhyodacite — ancient igneous formations that resist chemical weathering and contribute negligible dissolved calcium or magnesium. The closed, protected nature of Melbourne Water's catchments, undisturbed since the late 19th century, preserves this consistently low mineral profile throughout the entire metropolitan distribution network, including the northern inner suburban zone served from the Yarra Ranges supply corridor.

Reservoir residents enjoy very low limescale accumulation — taps, kettles, and shower screens rarely require descaling more than once every few months. Hot water systems accumulate negligible scale throughout their service life, reducing maintenance costs and sustaining energy efficiency. Some households install a benchtop carbon filter for improved taste, as ultra-soft, low-TDS water can occasionally seem slightly flat. Yarra Valley Water provides water quality information at yvw.com.au, with all ADWG standards consistently met throughout the Reservoir supply zone.