Miranda Water Hardness & Quality Report (2026)

Sydney Water provides the reticulated supply to Miranda, a suburb in the Sutherland Shire, Greater Sydney, NSW, Australia. The primary source is Warragamba Dam on the Warragamba River, with supplementary water drawn from other reservoirs like Prospect, Cordeaux, Avon, and Woronora. Over five million residents across the metropolitan area are served by major treatment facilities, including the Prospect Water Filtration Plant. Miranda's water enters this integrated network without local groundwater augmentation. The catchment area, spanning 9,000 square kilometers of forested uplands, is mainly the Warragamba Dam catchment.

Geologically, the area is dominated by Triassic-age Hawkesbury Sandstone and underlying Narrabeen Group sediments. These rock types are rich in quartz and contain few carbonate minerals. Because of this low-carbonate composition, they release minimal dissolved calcium and magnesium into the water. This results in a naturally soft water supply for Miranda, with little potential for high mineralisation. Surface runoff from the Blue Mountains uplands also contributes to keeping mineral levels low.

Because the water is soft, you'll notice minimal limescale buildup on your fixtures, kettles, and heating elements. This can help extend the lifespan of your appliances with less frequent maintenance. Soap lathers easily, which is a benefit for laundry and personal washing. A water softener isn't generally recommended for this supply. You might want to occasionally descale coffee machines or irons if you notice any spotting from the naturally occurring low-level minerals. The water quality parameters, including pH, chlorine, TDS, and turbidity, are all within Australian Drinking Water Guidelines.