Woonona Water Hardness & Quality Report (2026)

Sydney Water supplies Woonona and the surrounding Illawarra region, including Woonona East and Corrimal, with water primarily drawn from Warragamba Dam on the Warragamba River. This main source is supplemented by water from other reservoirs like Woronora, Cataract, Cordeaux, and Nepean. Treatment for this extensive supply network takes place at major facilities such as the Prospect Water Filtration Plant, with water then distributed through a vast system of pipes. The catchment area itself covers the Sydney Basin, drawing from the upper Nepean-Hawkesbury River system which flows through Paleozoic sandstones and Triassic sedimentary formations.

The geology underlying the Sydney Basin catchment is key to the water's character. Predominantly, the Hawkesbury Sandstone and the underlying Narrabeen Group shales dominate the landscape. These rock types are rich in quartz and contain very little limestone or dolomite. Because these carbonate minerals are largely absent, the water doesn't pick up significant amounts of calcium and magnesium as it flows through the Sydney Basin and coastal aquifer systems, contributing to its naturally soft profile.

This very soft water means homeowners in Woonona can expect fewer issues with limescale buildup on faucets, inside kettles, and on heating elements. Consequently, appliances like water heaters, dishwashers, and washing machines tend to last longer and operate more efficiently without the need for frequent descaling. You'll also find that soaps and detergents lather up beautifully, providing a better cleaning experience and leaving skin and hair feeling softer. Because the water is so soft, there's no need for a water softener system. The water quality reports show excellent results, with a pH of 7.8, fluoride at 1.03 mg/L, chlorine at 0.45 mg/L, TDS at 72 mg/L, and turbidity at a very low 0.13 NTU.