Wollongong city centre Water Hardness & Quality Report (2026)
Water Hardness
Source
reservoir
pH Level
7.4
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
148.3 mg/L
Est. Daily Cost
A$0.25
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 Wollongong city centre, your appliances are currently losing 11% efficiency due to mineral buildup.
| Appliance | In Wollongong city centre | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7 yrs | 8.5 yrs | -18% |
| Washing Machine | 10.7 yrs | 12 yrs | -11% |
| Water Heater | 12.4 yrs | 15 yrs | -17% |
Regional Water Comparison
How Wollongong city centre compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ Wollongong city centre, New South Wales | 79.5 mg/L | 🟡 Moderately Hard | reservoir |
| Wollongong, New South Wales | 35 mg/L | 🟢 Soft | reservoir |
| Figtree, New South Wales | 60 mg/L | 🟡 Moderately Hard | reservoir |
| Woonona, New South Wales | 153 mg/L | 🟠 Hard | reservoir |
| Dapto, New South Wales | 20.5 mg/L | 🟢 Soft | reservoir |
National Benchmark
How Wollongong city centre compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Wollongong city centre | 79.5 mg/L | 🟡 Low |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
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What Makes Wollongong city centre's Water Unique?
Local geology and source profile
Wollongong City Centre's drinking water is supplied by Sydney Water, drawing from Cordeaux Dam and the Avon Dam catchment system on the Illawarra Escarpment and Southern Highlands in New South Wales. Water hardness in Wollongong City Centre is measured at 79.5 mg/L — classified as slightly hard — within the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. Wollongong — New South Wales's third-largest city, Australia's most significant steel-producing centre at the foot of the Illawarra Escarpment between the coastal escarpment and the Tasman Sea — benefits from relatively soft supply characteristic of the escarpment reservoir catchments, harder than central Sydney but softer than the heavier western Sydney zones.
Wollongong's slightly elevated hardness reflects the Hawkesbury Sandstone and Permian coalfield catchment geology of the Illawarra Escarpment dam catchments. The Cordeaux and Avon dams collect runoff from the Southern Highlands and Illawarra Escarpment — where Triassic Hawkesbury Sandstone and Permian Illawarra Coal Measures overlie the Sydney Basin basement — contributing moderate calcium and silica dissolution relative to the pure granite supply of some catchments. The 79.5 mg/L at Wollongong city centre reflects this intermediate catchment geology blend, producing supply distinctly softer than the western Sydney Nepean corridor but slightly harder than the standard urban Sydney inner supply.
Wollongong City Centre residents can expect occasional light to moderate limescale on taps and in kettles — descaling every two to three months is typically adequate. Hot water systems accumulate minimal to moderate scale. Sydney Water provides water quality information at sydneywater.com.au, with all ADWG health standards consistently met. The slightly elevated lead reading (0.002 mg/L) warrants briefly running the cold tap before use in the many heritage commercial and residential buildings of the Wollongong city centre precinct along Crown Street.
Geology & Source: Supplied by Sydney Water from Cordeaux Dam and the Avon Dam system on the Illawarra Escarpment and Southern Highlands — the Wollongong City Centre supply carries slightly hard water at 79.5 mg/L, reflecting the Illawarra escarpment Hawkesbury Sandstone and Permian coalfield terrain catchment geology that moderately elevates hardness above the standard Sydney supply.