Mascot Water Hardness & Quality Report (2026)

Sydney Water provides the supply to Mascot, a suburb within the Bayside Council area of New South Wales. The primary water source originates from the Warragamba Dam, the main reservoir, with additional water drawn from Woronora Dam, Nepean Dam, and Avon Dam. This raw water is then processed at significant treatment facilities, including the Prospect Water Filtration Plant, North Richmond, and Waragamba. The treatment process involves several stages: coagulation, flocculation, sedimentation, filtration, and chlorination, before the water is distributed to residents via an extensive network of pipelines. The catchment area itself is vast, covering much of the Greater Sydney region within the Hawkesbury-Nepean watershed and is notably protected within national parks, limiting development.

The geology influencing the water quality in this region is characterized by the prevalence of Hawkesbury Sandstone, a formation dating back to the Triassic period. This sandstone is part of the larger Sydney Basin sequence and is interbedded with minor layers of shale and claystone, along with sediments from the underlying Narrabeen Group. Crucially, the absence of significant carbonate rocks like limestone or dolomite, and the dominance of sandstone with its sandy soils, means that dissolved minerals, particularly calcium and magnesium, are not readily leached into the water. This geological makeup is the reason for the area's characteristically soft water.

Because the water is soft, homeowners in Mascot will find that appliances like kettles, coffee machines, and water heaters are less prone to limescale buildup, which can extend their lifespan. Soap and detergents will lather more easily, meaning less product is needed for cleaning. While a water softener isn't necessary, it is advisable to monitor older copper pipes for potential corrosion due to the water's low mineral content, which offers less natural buffering. The water's pH is 7.8, and its total dissolved solids are 137 mg/L, well within the recommended guidelines. Although E. coli was detected at 1 org/100mL in some samples, exceeding the zero-tolerance standard, the overall water quality is rated as excellent.