Kogarah Water Hardness & Quality Report (2026)
Water Hardness
Source
reservoir
pH Level
7.9
neutral = 7.0
Lead
0.004 mg/L
✓ Below action level
TDS
372.1 mg/L
Est. Daily Cost
A$0.52
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 Kogarah, your appliances are currently losing 22% efficiency due to mineral buildup.
| Appliance | In Kogarah | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 4.1 yrs | 8.5 yrs | -52% |
| Washing Machine | 7.5 yrs | 12 yrs | -38% |
| Water Heater | 9 yrs | 15 yrs | -40% |
Regional Water Comparison
How Kogarah compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ Kogarah, New South Wales | 165.5 mg/L | 🟠 Hard | reservoir |
| Carlton, New South Wales | 198 mg/L | 🔴 Very Hard | reservoir |
| Rockdale, New South Wales | 26 mg/L | 🟢 Soft | reservoir |
| Sans Souci, New South Wales | 52 mg/L | 🟢 Soft | reservoir |
| Bexley, New South Wales | 117.5 mg/L | 🟡 Moderately Hard | reservoir |
National Benchmark
How Kogarah compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Kogarah | 165.5 mg/L | 🟠 Moderate |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
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What Makes Kogarah's Water Unique?
Local geology and source profile
Kogarah's drinking water is supplied by Sydney Water, treated at the Prospect Water Filtration Plant with a significant Hawkesbury-Nepean component distributed through the southern Sydney supply network for the Georges River LGA inner southern Sydney distribution in New South Wales. Water hardness in Kogarah is measured at 165.5 mg/L — classified as moderately hard, approaching the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. Kogarah — the commercial centre of the Georges River LGA on the northern bank of the Georges River estuary, known for its bustling railway station precinct, the Kogarah Town Centre, and proximity to Carss Park on Kogarah Bay — receives one of the harder inner Sydney supplies, in sharp contrast to the soft Cronulla (57.5 mg/L) just to the south in the adjacent Sutherland Shire.
Kogarah's elevated hardness reflects a proportionally significant Hawkesbury-Nepean component in the southern inner Sydney Georges River Prospect distribution blend. The Hawkesbury-Nepean system traverses the Cumberland Plain alluvial terrain and Triassic carbonate-cemented sedimentary formations — dissolving substantial calcium bicarbonate before Prospect treatment. The Kogarah Georges River inner southern distribution sub-zone receives a noticeably higher Hawkesbury-Nepean fraction than the adjacent Sutherland Shire soft zones, reflecting the distinct supply routing differential across the southern Sydney distribution network.
Kogarah residents face moderate to heavy limescale build-up on taps, shower screens, and in kettles — descaling every three to four weeks is typical. Hot water systems benefit from annual inspection. The elevated lead reading (0.004 mg/L) warrants briefly running the cold tap before use in older Kogarah homes. Sydney Water provides water quality information at sydneywater.com.au, with all ADWG health standards consistently met. A point-of-use filter is a practical investment for the Kogarah community and the suburb's active commercial railway precinct.
Geology & Source: Supplied by Sydney Water via the Prospect Water Filtration Plant with a significant Hawkesbury-Nepean component distributed through the southern Sydney supply network — the Kogarah Georges River LGA inner south supply carries moderately hard water at 165.5 mg/L with elevated TDS of 372.1 mg/L, among the harder inner Sydney sub-zones, reflecting the elevated Hawkesbury-Nepean proportion in the southern inner Sydney Georges River distribution corridor.