St Clair 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
43.2 mg/L
Est. Daily Cost
A$0.08
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 St Clair, your appliances are currently losing 4% efficiency due to mineral buildup.
| Appliance | In St Clair | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8.7 yrs | 8.5 yrs | — |
| Washing Machine | 12.6 yrs | 12 yrs | — |
| Water Heater | 14.5 yrs | 15 yrs | -3% |
Regional Water Comparison
How St Clair compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ St Clair, New South Wales | 26.5 mg/L | 🟢 Soft | reservoir |
| Mount Druitt, New South Wales | 30.5 mg/L | 🟢 Soft | reservoir |
| Rooty Hill, New South Wales | 186 mg/L | 🔴 Very Hard | reservoir |
| Kingswood Park, New South Wales | 58.5 mg/L | 🟢 Soft | reservoir |
| Doonside, New South Wales | 140 mg/L | 🟠 Hard | reservoir |
National Benchmark
How St Clair compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ St Clair | 26.5 mg/L | 🟢 None |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
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What Makes St Clair's Water Unique?
Local geology and source profile
St Clair's drinking water is supplied by Sydney Water, treated at the Prospect Water Filtration Plant predominantly drawing from Warragamba Dam for the Penrith LGA western Sydney distribution in New South Wales. Water hardness in St Clair is measured at 26.5 mg/L — classified as soft — within the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. St Clair, in the Penrith LGA at the foot of the Blue Mountains west of Sydney — a large residential suburb known for the Eric Dodd Fields sporting complex and Northhaven Village — receives a predominantly Warragamba-dominant supply blend, remarkably softer than adjacent Glenmore Park (91 mg/L) in the same Penrith LGA despite geographic proximity, illustrating the dramatic sub-zone supply variation within Sydney Water's outer western distribution network.
St Clair's soft supply reflects the predominantly Warragamba Dam fraction in the local Prospect plant distribution blend. Warragamba Dam collects from the Blue Mountains catchment draining across Triassic Hawkesbury Sandstone — silica-rich, calcium-poor formations contributing negligible dissolved minerals — immediately above the Nepean Gorge adjacent to the Penrith LGA boundary. The St Clair distribution node sits at a supply pathway that draws heavily from the Blue Mountains Warragamba supply, with minimal Nepean river plain contribution, unlike the Glenmore Park node which receives a proportionally higher Nepean component.
St Clair residents enjoy very low limescale accumulation on taps, in kettles, and around shower fittings — descaling is an occasional maintenance task. Hot water systems accumulate minimal scale. Sydney Water provides water quality information at sydneywater.com.au, with all ADWG health standards consistently met. St Clair's soft supply contrasts markedly with the harder western Sydney supply zones just a few kilometres away, and the very low lead reading (0.001 mg/L) confirms the high supply quality at this Blue Mountains fringe distribution node.
Geology & Source: Supplied by Sydney Water from the Prospect Water Filtration Plant predominantly drawing from Warragamba Dam — the St Clair Penrith Blue Mountains fringe supply carries very soft water at 26.5 mg/L, reflecting a predominantly Warragamba-dominant supply blend at this specific distribution node at the Penrith LGA Blue Mountains western fringe, markedly softer than adjacent Glenmore Park (91 mg/L) in the same LGA.