Brisbane Water Hardness & Quality Report (2026)

Brisbane's drinking water is supplied by Queensland Urban Utilities (QUU), with water sourced and treated by Seqwater from the Wivenhoe Dam on the Brisbane River and the Somerset Dam upstream in south-east Queensland. Water hardness in Brisbane is measured at 95 mg/L — classified as moderately hard — comfortably within the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L set by NHMRC. The Wivenhoe Dam's capacity of approximately 1,165 gigalitres provides the bulk of south-east Queensland's storage.

Brisbane's moderate hardness is shaped by its catchment geology. The Wivenhoe and Somerset catchments drain through Lockyer Valley alluvium and sedimentary sandstone of the d'Aguilar Range, where water percolates through calcium-bearing alluvial deposits before entering the storage system. This geology contributes a modest but consistent mineral load — enough to produce noticeable though manageable hardness in the final treated supply.

At 95 mg/L, Brisbane households will notice gradual limescale deposits on tap fittings and in kettles, though build-up is typically moderate and manageable with descaling every few months. Hot water systems may accumulate some scale on heating elements over time, so annual maintenance checks are worthwhile. Under Queensland water restrictions, limiting outdoor watering and car washing helps reduce overall household consumption — and keeping indoor appliances well maintained becomes a practical way to extend their service life.