Wantirna South Water Hardness & Quality Report (2026)
Water Hardness
Source
reservoir
pH Level
7.4
neutral = 7.0
Lead
0.003 mg/L
✓ Below action level
TDS
106 mg/L
Est. Daily Cost
A$0.17
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 Wantirna South, your appliances are currently losing 7% efficiency due to mineral buildup.
| Appliance | In Wantirna South | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7.8 yrs | 8.5 yrs | -8% |
| Washing Machine | 11.6 yrs | 12 yrs | -3% |
| Water Heater | 13.4 yrs | 15 yrs | -11% |
Regional Water Comparison
How Wantirna South compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ Wantirna South, Victoria | 54.5 mg/L | 🟢 Soft | reservoir |
| Wantirna, Victoria | 54.5 mg/L | 🟢 Soft | reservoir |
| Wheelers Hill, Victoria | 17 mg/L | 🟢 Soft | reservoir |
| Vermont South, Victoria | 16.5 mg/L | 🟢 Soft | reservoir |
| Vermont, Victoria | 78.5 mg/L | 🟡 Moderately Hard | reservoir |
National Benchmark
How Wantirna South compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Wantirna South | 54.5 mg/L | 🟢 None |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
Bring Boronia-quality water to your Wantirna South home
Shop water softeners on Amazon.com →
What Makes Wantirna South's Water Unique?
Local geology and source profile
Wantirna South's drinking water is supplied by South East Water as water retailer, with bulk supply from Melbourne Water drawn from the Upper Yarra Reservoir and Thomson Reservoir catchments in the Yarra Ranges, Victoria. Water hardness in Wantirna South is measured at 54.5 mg/L — classified as soft — well below the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. Wantirna South, in the Knox LGA — a large outer eastern residential suburb adjacent to Knox City shopping centre and Bayswater Creek — receives soft Yarra Ranges supply, notably harder than the adjacent extraordinarily soft Boronia sub-zone (5 mg/L) in the same Knox LGA, reflecting the very fine distribution sub-zone variation within Melbourne's eastern supply corridor.
Wantirna South's soft supply stems from Melbourne Water's protected Yarra Ranges catchments. The Upper Yarra and Thomson storages collect runoff across Devonian granite and rhyodacite — chemically resistant igneous terrain contributing negligible dissolved minerals. The Wantirna South distribution sub-zone receives predominantly direct Yarra Ranges reservoir supply, producing 54.5 mg/L — significantly more mineral-loaded than the adjacent Boronia distribution node (5 mg/L) despite geographic proximity, reflecting differences in supply delivery pathways and pipeline routing across the Knox LGA eastern distribution network.
Wantirna South residents enjoy very low limescale accumulation on taps, in kettles, and around shower fittings — descaling every two to three months is generally adequate. Hot water systems accumulate minimal scale throughout their service life. The elevated lead reading (0.003 mg/L) warrants briefly running the cold tap before use in older homes. South East Water provides water quality information at southeastwater.com.au, with all ADWG health standards consistently met throughout the Knox outer east supply zone.
Geology & Source: Supplied by South East Water (water retailer) and Melbourne Water (wholesale) from the Upper Yarra Reservoir and Thomson catchment systems — the Wantirna South Knox outer east Melbourne supply carries soft water at 54.5 mg/L, characteristic of the direct Yarra Ranges reservoir supply to the Knox foothills corridor, adjacent to the extraordinarily soft Boronia sub-zone (5 mg/L) in the same Knox LGA.