Dee Why Water Hardness & Quality Report (2026)
Water Hardness
Source
reservoir
pH Level
7.2
neutral = 7.0
Lead
0.001 mg/L
✓ Below action level
TDS
53.9 mg/L
Est. Daily Cost
A$0.10
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 Dee Why, your appliances are currently losing 4% efficiency due to mineral buildup.
| Appliance | In Dee Why | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8.5 yrs | 8.5 yrs | — |
| Washing Machine | 12.4 yrs | 12 yrs | — |
| Water Heater | 14.3 yrs | 15 yrs | -5% |
Regional Water Comparison
How Dee Why compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ Dee Why, New South Wales | 32.5 mg/L | 🟢 Soft | reservoir |
| Manly, New South Wales | 184 mg/L | 🔴 Very Hard | reservoir |
| Frenchs Forest, New South Wales | 101 mg/L | 🟡 Moderately Hard | reservoir |
| Mona Vale, New South Wales | 70.5 mg/L | 🟡 Moderately Hard | reservoir |
| Pittwater, New South Wales | 107.5 mg/L | 🟡 Moderately Hard | reservoir |
National Benchmark
How Dee Why compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Dee Why | 32.5 mg/L | 🟢 None |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
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What Makes Dee Why's Water Unique?
Local geology and source profile
Dee Why's drinking water is supplied by Sydney Water, treated at the Prospect Water Filtration Plant predominantly drawing from Warragamba Dam and the integrated Hawkesbury-Nepean reservoir system, serving the Northern Beaches LGA coastal north corridor in New South Wales. Water hardness in Dee Why is measured at 32.5 mg/L — classified as soft — within the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. Dee Why, on the Northern Beaches peninsula — home to Long Reef, Dee Why Lagoon, and one of Sydney's most popular northern surf beaches — receives a Warragamba-dominant supply blend that delivers characteristically soft water consistent with the Northern Beaches peninsula corridor, similar to Mosman (40.5 mg/L) and Pittwater's soft northern supply.
Dee Why's soft supply reflects the predominantly Warragamba Dam component in the Northern Beaches peninsula distribution blend. Warragamba Dam collects from the Blue Mountains and Southern Highlands catchment draining across Triassic Hawkesbury Sandstone — silica-rich, calcium-poor formations contributing negligible dissolved minerals. The Northern Beaches peninsula corridor receives a supply blend with a high Warragamba fraction and minimal Hawkesbury-Nepean river component, delivering softness well below the standard Sydney average at the Dee Why distribution node.
Dee Why residents enjoy minimal limescale accumulation on taps, in kettles, and around shower fittings — descaling every two to three months is typically adequate. Hot water systems accumulate minimal scale throughout their service life. Sydney Water provides water quality information at sydneywater.com.au, with all ADWG health standards consistently met. The soft supply complements the Northern Beaches lifestyle for Dee Why's beach community, and the very low lead reading (0.001 mg/L) confirms clean, consistently safe supply throughout this popular northern coastal suburb.
Geology & Source: Supplied by Sydney Water from the Prospect Water Filtration Plant predominantly drawing from Warragamba Dam — the Dee Why Northern Beaches coastal north Sydney distribution carries very soft water at 32.5 mg/L, reflecting the predominantly Warragamba-dominant supply blend typical of the Northern Beaches peninsula corridor, with minimal Hawkesbury-Nepean component reaching this coastal northern supply zone.