Preston Water Hardness & Quality Report (2026)

Preston'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 Preston is measured at 58.5 mg/L — classified as soft — well within the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. Preston, in Melbourne's inner north Darebin LGA, is historically connected to Melbourne's reservoir water system — the suburb is even named for its historic proximity to the former Preston Reservoir, a key distribution point in Melbourne's early water network.

Preston's soft supply originates from Melbourne Water's protected Yarra Ranges catchments. 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 minerals. The slightly higher hardness at Preston (58.5 mg/L) compared to the Melbourne CBD (41.5 mg/L) reflects the northern inner urban distribution pathway, which picks up modest additional mineral content from the pipeline infrastructure through the established north Melbourne suburban corridor.

Preston residents enjoy low limescale accumulation on tap fittings, in kettles, and around shower fittings — descaling every two to three months is generally adequate. Hot water systems accumulate minimal scale throughout their service life. The elevated lead reading (0.003 mg/L) warrants running the cold tap briefly before use in Preston's extensive stock of pre-1970 housing. Yarra Valley Water provides water quality information at yvw.com.au, with all ADWG health standards consistently met throughout the Darebin supply network.