Ferntree Gully Water Hardness & Quality Report (2026)
Water Hardness
Source
reservoir
pH Level
7.3
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
81.3 mg/L
Est. Daily Cost
A$0.14
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 Ferntree Gully, your appliances are currently losing 6% efficiency due to mineral buildup.
| Appliance | In Ferntree Gully | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8.2 yrs | 8.5 yrs | -4% |
| Washing Machine | 12 yrs | 12 yrs | — |
| Water Heater | 13.9 yrs | 15 yrs | -7% |
Regional Water Comparison
How Ferntree Gully compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ Ferntree Gully, Victoria | 43.5 mg/L | 🟢 Soft | reservoir |
| Boronia, Victoria | 5 mg/L | 🟢 Soft | reservoir |
| Bayswater, Victoria | 93.5 mg/L | 🟡 Moderately Hard | reservoir |
| Wantirna South, Victoria | 54.5 mg/L | 🟢 Soft | reservoir |
| Rowville, Victoria | 99.5 mg/L | 🟡 Moderately Hard | reservoir |
National Benchmark
How Ferntree Gully compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Ferntree Gully | 43.5 mg/L | 🟢 None |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
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What Makes Ferntree Gully's Water Unique?
Local geology and source profile
Ferntree Gully's drinking water is supplied by South East Water as water retailer, with bulk supply from Melbourne Water drawn from the Thomson Reservoir and Upper Yarra Reservoir catchments in the Yarra Ranges, Victoria. Water hardness in Ferntree Gully is measured at 43.5 mg/L — classified as soft — well within the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. Ferntree Gully, in the Knox LGA nestled at the base of the Dandenong Ranges foothills, receives Melbourne Water's Yarra Ranges supply through the eastern distribution corridor, with softness consistent with the near-source reservoir supply character for this part of Melbourne's outer south-east.
Ferntree Gully's soft supply reflects Melbourne Water's protected Yarra Ranges catchments. The Thomson and Upper Yarra storages collect runoff draining across Devonian granite and metamorphic rhyodacite of the Victorian Alps foothills — terrain closely adjacent to the Dandenong Ranges national parks that border Ferntree Gully's residential areas. The proximity of the distribution corridor to the eastern source catchments means minimal additional mineral pickup along the supply pipeline, consistent with the 43.5 mg/L hardness at the Ferntree Gully tap.
Ferntree Gully residents benefit from 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. South East Water provides water quality information at southeastwater.com.au, with all ADWG health standards consistently met throughout the Knox supply zone. A benchtop carbon filter is a popular option for residents who enjoy improved drinking water taste, as the soft water can occasionally carry faint natural notes after rainfall across the Dandenong Ranges bushland catchment areas adjacent to the Ferntree Gully residential community.
Geology & Source: Supplied by South East Water (water retailer) and Melbourne Water (wholesale) from the Thomson Reservoir and Upper Yarra Reservoir catchments in the Yarra Ranges — the Ferntree Gully Knox outer south-east Melbourne supply carries soft water at 43.5 mg/L, consistent with the near-source eastern Yarra Ranges supply corridor serving the foothills communities at the base of the Dandenong Ranges.