Green Valley Water Hardness & Quality Report (2026)

Sydney Water supplies Green Valley, drawing primarily from Warragamba Dam on the Warragamba River. This surface water is supplemented by other reservoirs like Prospect, Avon, and Woronora. Treatment for the vast majority of Sydney residents, including those in Green Valley, happens at major facilities such as the Prospect Water Filtration Plant. Here, processes including coagulation, filtration, disinfection, and fluoridation are employed. The catchment area, which spans the Warragamba River watershed in the Blue Mountains and Southern Highlands, is characterized by Triassic Hawkesbury Sandstone and Narrabeen Group shales, along with some Permian coal measures.

Geologically, the region lacks significant limestone or dolomite karst formations. This means the underlying rocks, primarily the siliceous Hawkesbury Sandstone and other Sydney Basin sedimentary rocks, contribute minimal dissolved minerals to the water. The protected nature of the Warragamba Dam catchment further limits mineral dissolution. Any surface flows that pass through granitic and basaltic terrains in the upper catchment add very little calcium and magnesium. Even some blending with Sydney region groundwater from Quaternary alluvial aquifers doesn't significantly alter the water's naturally soft character.

Because the water is soft, you won't find scale buildup on your plumbing fixtures, inside kettles, or on heating elements in appliances. This means less need for descaling and potentially longer lifespans for items like water heaters and dishwashers. Soap and detergent lather up much more easily, so you might find you use less product. A water softener isn't necessary here; in fact, it could potentially lead to pipe corrosion by removing too many beneficial minerals. Sydney Water adjusts the pH to between 7.0 and 8.0, and tests show negligible levels of lead and copper, with no reported PFAS exceedances.