Colac Water Hardness & Quality Report (2026)

Barwon Water is the regional utility serving Colac and surrounding areas in southwest Victoria, Australia, including the Geelong and Colac regions. Their primary sources are surface water from the Barwon River catchment, Lake Colac, and local reservoirs, with the Barwon Downs borefield providing supplementary supply. Water is treated at facilities like the Colac Water Treatment Plant, which employs coagulation, filtration, disinfection, and fluoridation. This system delivers to over 300,000 people across the City of Colac Otway and adjacent shires.

The watershed spans the Barwon River basin in the Otway Ranges, a temperate rainforest area with catchments protected from intensive agriculture. The underlying geology features Quaternary basalts and Tertiary sediments overlying Cretaceous rocks of the Otway Basin. Limited limestone formations contribute minimal dissolved calcium and magnesium. Surface waters pick up few minerals as they flow over granitic and basaltic terrains, resulting in characteristically soft water low in hardness ions.

Because the water is soft, Colac's supply poses no scaling risks to plumbing, reducing buildup in pipes, kettles, and heaters. Appliances like dishwashers and washing machines perform efficiently without softeners, and soap lathering is excellent. No maintenance for scale is needed, though soft water can sometimes feel 'slippery' and may slightly increase corrosion risk in metal pipes. Softeners are unnecessary and not recommended for this naturally soft supply.