Orange Water Hardness & Quality Report (2026)

Orange Water Services, operated by Orange City Council in New South Wales, Australia, supplies treated drinking water to the city of Orange and surrounding areas in the Central Tablelands. Primary sources include surface water from Suma Park Dam on Summerhill Creek and groundwater from bores in the Orange Basalt Aquifer. Water is treated at the Suma Park Water Treatment Plant using coagulation, flocculation, sedimentation, filtration, and chlorination, with additional blending from groundwater sources as needed to meet demand for the 40,000+ residents. The supply originates from the Molonglo River catchment within the Macquarie-Barwon watershed, encompassing Tertiary basalt flows over Paleozoic sedimentary bedrock of the Lachlan Orogen.

These volcanic and carbonate-influenced formations contribute minerals like calcium and magnesium, shaping a moderately mineralised water character. Rainfall on the basalt plateau infiltrates or runs off into reservoirs, interacting with reactive geology that imparts dissolved solids, while deeper groundwater extraction enhances mineral content from fractured aquifers. The Orange Basalt Aquifer formations, of Tertiary volcanic origin from the Nandewar Volcano Province, overlay sedimentary rocks of the Lachlan Fold Belt including Ordovician to Silurian mudstones and sandstones. Surface waters start soft from rainfall but pick up minerals from basaltic weathering rich in calcium and magnesium, while groundwater dissolves carbonates from underlying limestones, contributing to a mineralised profile typical of volcanic and sedimentary interfaces in central NSW.

As a soft supply, Orange water causes minimal scale buildup in pipes, kettles, and appliances, reducing maintenance needs compared to harder regions. Hot water systems and dishwashers experience little limescale, though occasional checks for sediment are advised. A water softener is not recommended, as it could strip beneficial minerals without significant scaling issues; instead, simple descaling with vinegar suffices annually for longevity. Water quality meets Australian Drinking Water Guidelines, with pH typically 7.2-7.8 and full compliance for lead and copper at the tap. No notable PFAS detections reported; occasional low-level iron or manganese from groundwater is managed through treatment. Disinfection uses chlorination with residuals of 0.2-0.6 mg/L, and fluoridation maintains dental health levels. Annual reports confirm no exceedances for regulated contaminants like trihalomethanes or nitrates.