Randwick Water Hardness & Quality Report (2026)
Water Hardness
Source
reservoir
pH Level
7.1
neutral = 7.0
Lead
0.001 mg/L
✓ Below action level
TDS
52 mg/L
Est. Daily Cost
A$0.10
energy & soap waste
Source: BOM National Performance Report & ADWG · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Randwick, your appliances are currently losing 4% efficiency due to mineral buildup.
| Appliance | In Randwick | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8.6 yrs | 8.5 yrs | — |
| Washing Machine | 12.4 yrs | 12 yrs | — |
| Water Heater | 14.3 yrs | 15 yrs | -5% |
Regional Water Comparison
How Randwick compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ Randwick, New South Wales | 31.5 mg/L | 🟢 Soft | reservoir |
| Coogee, New South Wales | 109 mg/L | 🟡 Moderately Hard | reservoir |
| Kingsford, New South Wales | 83.5 mg/L | 🟡 Moderately Hard | reservoir |
| Kensington, New South Wales | 195 mg/L | 🔴 Very Hard | reservoir |
| Paddington, New South Wales | 174 mg/L | 🟠 Hard | reservoir |
National Benchmark
How Randwick compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Randwick | 31.5 mg/L | 🟢 None |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
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What Makes Randwick's Water Unique?
Local geology and source profile
Randwick's drinking water is supplied by Sydney Water, drawn from Warragamba Dam and the Woronora Dam reservoir system serving the eastern Sydney distribution network in New South Wales. Water hardness in Randwick is measured at 31.5 mg/L — classified as soft — well within the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. Randwick, adjacent to the University of New South Wales and Randwick Racecourse in Sydney's eastern suburbs, receives Sydney Water supply from the main Warragamba-sourced distribution network, with softness consistent with the characteristically low-mineral Sydney supply.
Randwick's soft supply traces directly to the Warragamba and Woronora catchment geology. Both storages drain through Triassic Hawkesbury Sandstone and Narrabeen Group shale in the Blue Mountains and southern Sydney Basin — silica-rich, calcium-poor formations that resist chemical weathering and contribute negligible dissolved minerals. The eastern Sydney distribution corridor, receiving a predominantly Warragamba-dominant supply blend from the Prospect treatment plant, consistently delivers soft water to the Randwick LGA's eastern coastal and suburban zones.
Randwick residents enjoy minimal limescale accumulation on tap fittings, in kettles, and around shower fittings — descaling is an occasional rather than routine task. Hot water systems accumulate very little scale throughout their service life. Sydney Water provides water quality information at sydneywater.com.au, with all ADWG health standards consistently met. A benchtop carbon filter is popular in Randwick households for improved taste, and the soft water is a benefit for the many student residences and the UNSW campus, where soft water supports comfortable everyday use and minimal appliance maintenance.
Geology & Source: Supplied by Sydney Water from the Warragamba Dam and Woronora Dam system serving the eastern Sydney distribution zone — the Randwick supply carries soft water at 31.5 mg/L, consistent with Sydney Water's characteristic Triassic Hawkesbury Sandstone catchment geology that contributes minimal dissolved minerals to the eastern Sydney supply.