Prestons Water Hardness & Quality Report (2026)

Residents of Prestons, New South Wales, receive their water supply from Sydney Water Corporation, a utility serving the broader Sydney metropolitan area. The main source of this water is Warragamba Dam, located on the Warragamba River. This primary supply is further augmented by water from several other reservoirs, including Prospect, Cordeaux, Avon, and Woronora. The water undergoes treatment at significant facilities like the Prospect Water Filtration Plant, which is responsible for supplying the southwestern parts of Sydney, including Prestons within the Liverpool City Council area. The utility provides water to more than 5 million people across Sydney, with Prestons being part of the Macarthur delivery zone.

The water's journey begins in the Sydney Basin, with catchments covering the Nattai, O'Hare Creek, and Lake Burragorang watersheds. This region is characterized by Triassic sandstone and shale bedrock, notably the Hawkesbury Sandstone. Crucially, there are no significant limestone aquifers in the vicinity, meaning the water naturally contains low levels of dissolved minerals, resulting in a soft water profile. The supply is predominantly fed by surface runoff from forested upland areas. This geological makeup provides a low-mineralized character, which requires minimal adjustments during the treatment process to address potential scaling issues.

Because the water is naturally soft, Sydney's supply presents minimal risk of scale buildup in household appliances. You'll find that hot water systems, kettles, and plumbing experience very little calcium accumulation, which translates to less frequent maintenance and a longer lifespan for these items. Soap lathers readily with this soft water, meaning you won't need to use as much, which can be gentler on your skin and hair. A water softener isn't really necessary; for any minor deposits that might appear due to occasional blending with other sources, a simple cleaning with vinegar is usually sufficient. Sydney Water carefully manages the water's pH, keeping it between 6.5 and 8.5, in line with the Australian Drinking Water Guidelines. Recent analyses have shown no significant concerns regarding lead, copper, or PFAS levels, and while turbidity can sometimes increase after heavy rainfall, the water consistently meets all health standards.