Randwick Water Hardness & Quality Report (2026)

Sydney Water supplies Randwick, a suburb in New South Wales, Australia, as part of its extensive network serving Greater Sydney. The water originates from a system of dams, primarily the Warragamba Dam on the Hawkesbury-Nepean River, and is supplemented by Woronora Dam, Prospect Reservoir, and others within the Greater Sydney catchment. After treatment at filtration plants like the Prospect Water Filtration Plant, this chlorinated and fluoridated surface water is delivered to residents. The Greater Sydney catchment is vast, covering 16,000 square kilometers, with the Warragamba Dam watershed in the Blue Mountains region being a major component.

The region's geology is characterized by Triassic-age Hawkesbury Sandstone and Narrabeen Group sediments. These rock types are predominantly quartz-rich and have a low carbonate content. This geological makeup means that minimal calcium and magnesium are leached into the water supply. Unlike areas with limestone or dolomite, the siliceous nature of these formations results in water with low mineralisation and very soft characteristics. Trace ions are introduced from shale interbeds, but these do not significantly harden the water.

This soft water means you'll likely notice minimal limescale buildup on your fixtures, in kettles, or on pipes. Appliances such as washing machines, dishwashers, and coffee makers are better protected from scaling damage and may last longer. You might also find that you need less soap and detergent for cleaning, as soft water lathers more easily and produces less soap scum. Because the water is naturally soft, a water softener isn't necessary for Randwick residents. While Sydney Water reports robust disinfection, E. coli was detected in some samples, which does not meet the zero-tolerance standard, though overall water quality is rated highly.