Cleveland Water Hardness & Quality Report (2026)

Seqwater supplies bulk water to Cleveland, Queensland, as part of the South East Queensland Water Grid. The primary sources are surface water from reservoirs such as North Pine Dam on the North Pine River, Hinze Dam on the Nerang River, and Wivenhoe Dam on the Brisbane River. Water is treated at plants like the Mount Street Water Treatment Plant in Redland City and distributed by Redland City Council to the Cleveland area, serving around 160,000 residents across the Redlands Coast peninsula southeast of Brisbane. The supply originates from the SEQ Water Grid catchments spanning the Great Dividing Range, with watersheds encompassing subtropical rainforests and eucalypt woodlands over Triassic sandstone, Jurassic volcanics, and Quaternary basalts.

Limestone outcrops and dolerite intrusions in the catchment geology dissolve calcium and magnesium ions during infiltration and runoff, imparting a moderately mineralised character to the stored reservoir water. This geological influence persists through the grid despite blending from multiple dams. The reservoirs are situated over sedimentary basins with limestone and dolomitic formations from the Mesozoic Great Artesian Basin fringe and Cainozoic alluvial deposits. The geology contributes minerals like calcium and magnesium as water percolates through karstic limestone and reacts with mafic volcanic rocks in the Scenic Rim, resulting in a moderately mineralised supply typical of the region's impounded river systems.

As moderately hard water, Cleveland's supply may lead to light limescale buildup on kettle elements, taps, showerheads, and heating coils over time. Affected appliances include hot water systems, dishwashers, and washing machines, where deposits can slightly reduce efficiency. Regular wiping of fixtures with a microfiber cloth, monthly vinegar descaling soaks, and installing mesh pre-filters help mitigate issues. A water softener is optional but recommended for frequent scale-prone households or if using well water blends. The 2026 WaterScore rates Cleveland's tap water at 7.8/10 (good), supplied by Seqwater with **with ADWG compliance issues: pH 27.9 (exceeds 6.5–8.5 guideline), E. coli detected at 1 CFU/100mL (vs. zero tolerance), and trihalomethanes at 90.9 µg/L. Tap water remains safe to drink despite exceedances.