Carnegie Water Hardness & Quality Report (2026)

The South East Water Corporation supplies Carnegie, a southeastern suburb of Melbourne in the City of Glen Eira, Victoria, Australia. This utility serves over 1.6 million people across numerous local government areas, including Bayside, Cardinia, Casey, Frankston, Glen Eira, Kingston, Knox, Maroondah, Monash, Whitehorse, and Yarra Ranges. The water supply is mixed, drawing primarily from protected surface catchments within the Greater Yarra catchment. Key sources include reservoirs like Thomson Reservoir, Sugarloaf Reservoir, and Cardinia Reservoir, all fed by runoff from the forested uplands of the Great Dividing Range. Groundwater is also utilized, sourced from bores such as Siloah and Kurumburra, tapping into aquifers in the Gippsland Basin and Port Phillip groundwater zones. Treated water is distributed via extensive networks after advanced filtration, disinfection, and fluoridation at major plants including Winneke, Millgrove, and Bullen.

The region's geology features sedimentary basins composed of granitic and sedimentary rocks from the Paleozoic to Mesozoic eras, feeding into reservoirs. Groundwater components tap into Quaternary alluvial and Tertiary sands within coastal basins. These formations, largely siliceous with peaty moorlands and minimal interaction with carbonate-rich rock, result in naturally soft water. This geological makeup contrasts sharply with the calcareous mallee soils found in inland Victoria, which typically produce harder water due to higher concentrations of dissolved calcium and magnesium leached from limestone.

Because Carnegie receives soft water, residents typically notice minimal scale buildup on fixtures, kettles, and pipes. This means appliances like dishwashers, washing machines, and hot water systems often require less maintenance and may last longer. Soap lathers readily, producing less scum, and many find their skin feels less dry after showering. A water softener is generally not necessary for this supply. While descaling might rarely be needed, checking other factors like chloramine levels can contribute to appliance longevity. South East Water adheres to the Australian Drinking Water Guidelines, employing treatments like microfiltration, ozonation, chloramination, and UV disinfection to ensure water quality and safety, with fluoride added at 1.0 mg/L.