Ferntree Gully Water Hardness & Quality Report (2026)

The water serving Ferntree Gully originates from the Thomson Reservoir and Upper Yarra Reservoir catchments. These vital sources are managed by Melbourne Water, which acts as the wholesale supplier. South East Water then retails this water to residents in the outer south-east Melbourne region. The supply route is designed to deliver soft water, reflecting the natural characteristics of the eastern Yarra Ranges supply corridor that feeds communities situated at the base of the Dandenong Ranges.

The geology underlying the Yarra Ranges is primarily composed of ancient granitic and metamorphic rock formations. These types of rocks are known for their low solubility, meaning they don't readily release minerals like calcium and magnesium into the water as it flows through. Consequently, the water collected from these areas, including the catchments for the Thomson Reservoir and Upper Yarra Reservoir, is naturally soft. This geological makeup is the key reason for the soft water characteristics observed in the supply to the Ferntree Gully area.

Residents might notice that soft water lathers soap more easily and requires less detergent for laundry and dishes. Because it doesn't contain high levels of hardness minerals, it's less likely to cause significant scale buildup in appliances like kettles, coffee makers, and particularly water heaters, potentially extending their lifespan. While specific taste preferences vary, many find soft water to be smoother. You won't need a water softener for this supply, and descaling efforts are generally minimal.