Leichhardt Water Hardness & Quality Report (2026)

Sydney Water supplies Leichhardt, an Inner West suburb, with drinking water drawn from a complex network of 13 supply zones. The primary sources are rainfall-fed reservoirs like Warragamba Dam, Prospect Reservoir, and Woronora Dam, situated within the catchment areas of the Hawkesbury-Nepean and Georges Rivers. Water undergoes rigorous treatment at major facilities, including the Prospect Water Filtration Plant, employing processes such as coagulation, filtration, disinfection, and fluoridation to meet the Australian Drinking Water Guidelines. This system serves millions of residents across Sydney's metropolitan region.

The underlying geology of the Leichhardt area features Triassic-age sedimentary formations, notably the Hawkesbury Sandstone and the Narrabeen Group shales and sandstones. These strata contain minimal limestone or dolomite, meaning they contribute very low levels of dissolved calcium and magnesium to the water. Consequently, the water naturally possesses a soft character. Surface runoff from granitic and basaltic terrains in the Blue Mountains further contributes to this low-mineralised profile, ensuring the water remains consistently soft even after treatment.

Because the water is naturally soft, homeowners in Leichhardt will notice minimal limescale buildup in appliances like kettles, washing machines, and dishwashers. This gentler water quality also benefits skin and hair. Plumbing fixtures are less prone to scale accumulation, and descaling is rarely necessary. You won't typically need a water softener, as issues like soap scum or reduced appliance efficiency are uncommon. A simple cleaning with vinegar is usually sufficient for any minor deposits. While the water quality is excellent overall, with a WaterScore of 8.9/10 and pH at 7.9, Sydney Water continues monitoring for E. coli to uphold strict guidelines.