Mulgrave Water Hardness & Quality Report (2026)

Mulgrave's drinking water is supplied by South East Water as water retailer, with bulk supply from Melbourne Water distributed through the outer south-eastern metropolitan network in Victoria. Water hardness in Mulgrave is measured at 112 mg/L — classified as moderately hard — within the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. Mulgrave, in the Monash LGA — home to Monash University's Clayton campus, Enterprise Drive business precinct, and Westfield Southland — receives supply from a distribution sub-zone with substantially elevated Winneke Water Treatment Plant contribution, producing 112 mg/L in remarkable contrast to adjacent Wheelers Hill (17 mg/L) in the same Monash LGA, illustrating Melbourne's extraordinary intra-LGA supply variation.

Mulgrave's elevated hardness reflects the significant Winneke Water Treatment Plant supply proportion at this outer south-east Monash distribution node. The Winneke plant at Yering Gorge draws from the Yarra River traversing Devonian basalt and alluvial valley terrain — dissolving substantially more calcium and magnesium than the protected granite reservoir catchments. The Mulgrave distribution sub-zone receives a proportionally high Winneke blend fraction compared to the very soft Wheelers Hill sub-zone immediately to its south, reflecting the complex Melbourne supply distribution where reservoir and WTP supply proportions vary dramatically at the sub-LGA scale.

Mulgrave residents face moderate to significant limescale accumulation on taps and in kettles — descaling every four to six weeks is typical. Hot water systems benefit from annual inspection and element maintenance. The elevated lead reading (0.005 mg/L) warrants briefly running the cold tap before use. South East Water provides water quality information at southeastwater.com.au, with all ADWG health standards consistently met throughout the Monash outer south-east supply zone.