Mona Vale 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
128.7 mg/L
Est. Daily Cost
A$0.22
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 Mona Vale, your appliances are currently losing 9% efficiency due to mineral buildup.
| Appliance | In Mona Vale | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7.3 yrs | 8.5 yrs | -14% |
| Washing Machine | 11 yrs | 12 yrs | -8% |
| Water Heater | 12.8 yrs | 15 yrs | -15% |
Regional Water Comparison
How Mona Vale compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ Mona Vale, New South Wales | 70.5 mg/L | 🟡 Moderately Hard | reservoir |
| Pittwater, New South Wales | 107.5 mg/L | 🟡 Moderately Hard | reservoir |
| Dee Why, New South Wales | 32.5 mg/L | 🟢 Soft | reservoir |
| Frenchs Forest, New South Wales | 101 mg/L | 🟡 Moderately Hard | reservoir |
| Manly, New South Wales | 184 mg/L | 🔴 Very Hard | reservoir |
National Benchmark
How Mona Vale compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Mona Vale | 70.5 mg/L | 🟡 Low |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
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What Makes Mona Vale's Water Unique?
Local geology and source profile
Mona Vale's drinking water is supplied by Sydney Water, treated at the Prospect Water Filtration Plant with a predominantly Warragamba Dam source and low Hawkesbury-Nepean component for the Northern Beaches LGA coastal distribution in New South Wales. Water hardness in Mona Vale is measured at 70.5 mg/L — classified as slightly hard — within the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. Mona Vale — a coastal suburb at the centre of the Northern Beaches LGA on Pittwater and Mona Vale Beach, known as the commercial hub of the northern Northern Beaches with the Mona Vale village shops, the Mona Vale Headland reserve, Bungan and Mona Vale surf beaches, and the Pittwater Hospital precinct — receives slightly elevated supply at the outer northern Northern Beaches Prospect distribution sub-zone.
Mona Vale's slightly elevated hardness reflects the moderate supply blend at the outer northern Northern Beaches LGA Prospect distribution. The predominantly Warragamba Dam contribution drains the Blue Mountains sandstone plateau and Kanangra–Boyd granite uplands — chemically resistant terrain contributing negligible dissolved minerals. The slight hardness elevation at 70.5 mg/L and TDS 128.7 mg/L reflects a moderate Hawkesbury-Nepean component or local Northern Beaches distribution routing contributing minor additional mineralisation at the outer Mona Vale coastal sub-zone, compared to the very soft inner Northern Beaches sub-zones.
Mona Vale residents can expect occasional light limescale on taps and in kettles — descaling every two to three months is typically adequate. Hot water systems benefit from periodic inspection. The low lead reading (0.002 mg/L) is excellent. Sydney Water provides water quality information at sydneywater.com.au, with all ADWG health standards consistently met. Mona Vale's Northern Beaches coastal community and the Pittwater Hospital precinct benefit from a safe supply meeting all ADWG standards.
Geology & Source: Supplied by Sydney Water via the Prospect Water Filtration Plant with predominantly Warragamba Dam and low Hawkesbury-Nepean component — the Mona Vale Northern Beaches coastal supply carries slightly hard water at 70.5 mg/L with TDS of 128.7 mg/L, reflecting the moderate supply blend at the outer northern Northern Beaches LGA Mona Vale Prospect distribution sub-zone.