Kellyville Ridge Water Hardness & Quality Report (2026)

Sydney Water Corporation supplies the residents of Kellyville Ridge in The Hills Shire, New South Wales. This area is part of the Greater Sydney water network, which draws from multiple sources to serve over 5 million people. The primary supply comes from Warragamba Dam, the main storage on the Warragamba River and Nattai Rivers catchment. Additional water is sourced from reservoirs like Prospect, Cordeaux, Woronora, and Tallowa Dam on the Shoalhaven River. During periods of drought, groundwater from alluvial aquifers along the Hawkesbury-Nepean River is used for blending.

Treatment of this mixed supply occurs at several major facilities. The Prospect Water Filtration Plant, with a capacity of 430 ML/day, serves northwest Sydney, including Kellyville Ridge. Its treatment process involves dissolved air flotation, ozonation, dual media filtration, chloramination, and fluoridation. Other plants, such as the Illawarra and Advanced Water Treatment plants, handle water from the Shoalhaven River.

The geology underpinning this water supply system is the Sydney Basin's Triassic sandstones and shales. Specifically, the Hawkesbury Sandstone aquifer is prevalent in the region. The watershed feeding Warragamba Dam features thin soils overlying resistant quartzites and shales, with minimal carbonate rock. This geological makeup results in water that is naturally soft, containing low levels of dissolved solids from both surface runoff and groundwater extraction. The dissolution of sandstone releases silica but few hardness ions, while clay shales buffer acidity without significantly adding calcium or magnesium. This results in a low-mineralised water chemistry characteristic of coastal southeastern Australia basins.

This soft water supply is beneficial for household appliances, significantly reducing limescale buildup in items like kettles, washing machines, and dishwashers, which helps extend their operational lifespan. Homeowners might find basic descaling every 6 to 12 months is sufficient. Soap lathers easily in soft water, potentially reducing usage by 20% to 30%. However, you might notice minor spotting on glassware or fabrics that feel less 'full' after washing. A water softener isn't generally needed for this supply; a basic sediment or carbon filter is usually adequate to address any sediment or chlorine taste. Laundry detergents perform optimally without any special adjustments. Sydney Water aims to maintain a pH between 6.5 and 8.5, typically around 7.2 to 7.8 after treatment. The system complies with Australian Drinking Water Guidelines for lead and copper, with corrosion control managed through pH and alkalinity adjustments. No PFAS exceedances were reported in the 2023-24 data. While occasional turbidity spikes can occur after heavy rain, typically below 1 NTU, enhanced coagulation processes manage this effectively.