Warrnambool Water Hardness & Quality Report (2026)

Wannon Water supplies drinking water to over 50,000 customers across 11 systems in southwest Victoria, Australia. The utility draws from protected surface water catchments, including Lake Warrnambool and the Merri River, supplemented by groundwater bores in the Curdie Valley aquifer. Major treatment facilities like the Warrnambool Water Treatment Plant employ a multi-stage process: screening, coagulation, filtration, disinfection with chloramine, and fluoridation. Raw water is sometimes sourced from Grampians Wimmera-Mallee Water Corporation. The primary watersheds span the Merri River basin and Otway Ranges catchments, where peaty soils and basalt geology contribute to low-mineral runoff.

The region's geology is a mix of volcanic basalts from the Newer Volcanics Province overlaying older Cretaceous and Paleogene formations. Surface waters from peaty moorlands and forested catchments yield very soft water low in dissolved minerals due to minimal contact with calcareous rocks. Groundwater from confined aquifers in the Eastern View Formation and Lower Strzelecki Group, particularly where limestone is present, can pick up higher calcium from karst features. This blend generally results in a soft water character, though some bores tapping limestone-influenced groundwater can be harder.

Because this supply is generally soft to moderately hard, scale buildup is minimal, sparing appliances like kettles, hot water systems, and dishwashers from significant deposits. Soap lathers easily, reducing detergent needs, though the very soft water component might cause minor corrosion in older pipes if untreated. Homeowners typically won't need a water softener, and installing one could potentially increase risks of lead leaching in older plumbing. Routine maintenance involves standard fixture flushing annually. Water quality meets Australian Drinking Water Guidelines, with pH typically between 7.5-8.5 post-treatment, and Wannon Water's 2022/23 report confirms compliance for lead, copper, and disinfection byproducts.