Cherrybrook Water Hardness & Quality Report (2026)
Water Hardness
Source
reservoir
pH Level
7.6
neutral = 7.0
Lead
0.003 mg/L
✓ Below action level
TDS
208.9 mg/L
Est. Daily Cost
A$0.33
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 Cherrybrook, your appliances are currently losing 14% efficiency due to mineral buildup.
| Appliance | In Cherrybrook | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6.1 yrs | 8.5 yrs | -28% |
| Washing Machine | 9.7 yrs | 12 yrs | -19% |
| Water Heater | 11.4 yrs | 15 yrs | -24% |
Regional Water Comparison
How Cherrybrook compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ Cherrybrook, New South Wales | 105.5 mg/L | 🟡 Moderately Hard | reservoir |
| West Pennant Hills, New South Wales | 71 mg/L | 🟡 Moderately Hard | reservoir |
| Castle Hill, New South Wales | 28 mg/L | 🟢 Soft | reservoir |
| Hornsby, New South Wales | 122 mg/L | 🟠 Hard | reservoir |
| Carlingford, New South Wales | 41 mg/L | 🟢 Soft | reservoir |
National Benchmark
How Cherrybrook compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Cherrybrook | 105.5 mg/L | 🟡 Low |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
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What Makes Cherrybrook's Water Unique?
Local geology and source profile
Cherrybrook's drinking water is supplied by Sydney Water, treated at the Prospect Water Filtration Plant blending Warragamba Dam and Hawkesbury-Nepean supply for the Hornsby LGA upper North Shore distribution in New South Wales. Water hardness in Cherrybrook is measured at 105.5 mg/L — classified as moderately hard — within the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. Cherrybrook, in the Hornsby LGA — a prestigious outer north-west Sydney residential suburb of large homes and bushland reserves adjacent to the Hills District boundary — receives supply with a significant Hawkesbury-Nepean component, consistent with the broader upper North Shore Hills corridor hardness pattern that includes Hornsby (122 mg/L), Chatswood (179.5 mg/L), and Kellyville (96 mg/L).
Cherrybrook's elevated hardness reflects the Hawkesbury-Nepean component in the upper North Shore Hills Hornsby Prospect distribution blend. The Hawkesbury-Nepean river system traverses the Cumberland Plain alluvial terrain and adjacent Triassic Hawkesbury Sandstone escarpment — dissolving moderate calcium bicarbonate before Prospect treatment. The Cherrybrook upper North Shore Hills distribution node receives a proportionally elevated Nepean-sourced supply fraction relative to the soft inner eastern and lower North Shore Sydney zones, raising hardness to 105.5 mg/L consistent with the broader upper North Shore hardness gradient.
Cherrybrook residents face moderate limescale build-up on taps and in kettles — descaling every three to four weeks is typical. Hot water systems benefit from annual inspection. The elevated lead reading (0.003 mg/L) warrants briefly running the cold tap before use in older established homes. Sydney Water provides water quality information at sydneywater.com.au, with all ADWG health standards consistently met. A water filter or scale inhibitor is a practical investment for Cherrybrook's predominantly owner-occupied prestige residential community in the upper North Shore Hills corridor.
Geology & Source: Supplied by Sydney Water from the Prospect Water Filtration Plant serving the Upper North Shore Hornsby-adjacent distribution — the Cherrybrook Hornsby LGA supply carries moderately hard water at 105.5 mg/L with elevated TDS of 208.9 mg/L, reflecting the Hawkesbury-Nepean supply proportion characteristic of the upper North Shore Hills Hornsby distribution corridor.