Como Water Hardness & Quality Report (2026)

The Water Corporation provides water to Como, a suburb within the City of South Perth, as part of the extensive Perth Metropolitan Water Supply Scheme. This vital service supplies over 1.9 million people across the Perth region. The water comes from a diverse mix of sources, including surface water collected in dams like Serpentine, Wungong, and Vasse Diversion located in the Darling Ranges. A significant portion, around 50%, is desalinated seawater from the Perth Seawater Desalination Plant at Kwinana, with smaller contributions from groundwater sources such as Jandakot Mound and Wanneroo aquifers. Treatment is sophisticated, involving reverse osmosis at the Kwinana Desalination Plant and conventional filtration with chlorination at facilities like the Harvey Water Treatment Plant.

The Como area's water quality is significantly shaped by the region's geology. The Darling Range catchments, part of the Swan-Avon River basin, feature granite and laterite plateaus. Beneath these lie sedimentary aquifers hosted within key geological formations. Northward, the Archaean Yilgarn Craton granites are prevalent, while the southern areas, including where Como is situated, are characterized by Phanerozoic sediments. Specifically, the Eocene Pinjarra Sandstone and the Cretaceous Leederville Formation are important, containing confined aquifers. Crucially, south of the Swan River, limestone-rich strata dominate. As water percolates through these limestones, it dissolves calcium and magnesium carbonates, resulting in a characteristically hard water supply with a high mineral content.

This very hard water contributes to noticeable limescale buildup within appliances such as kettles, hot water systems, and dishwashers, which can reduce their efficiency and shorten their lifespan. Homeowners often observe white deposits and spotting on faucets, glassware, and tiles after water evaporates. You'll also find that soap doesn't lather as easily, meaning more detergent is needed for cleaning tasks. To manage this, regular maintenance like monthly flushing of hot water system valves or using vinegar rinses for appliances can help. For persistent issues and to protect plumbing and appliances long-term, installing a water softener is frequently recommended, especially for households experiencing frequent scale problems.