Mount Martha Water Hardness & Quality Report (2026)
Water Hardness
Source
reservoir
pH Level
7
neutral = 7.0
Lead
0.001 mg/L
✓ Below action level
TDS
12.1 mg/L
Est. Daily Cost
A$0.02
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 Mount Martha, your appliances are currently losing 1% efficiency due to mineral buildup.
| Appliance | In Mount Martha | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 9.4 yrs | 8.5 yrs | — |
| Washing Machine | 13.3 yrs | 12 yrs | — |
| Water Heater | 15.3 yrs | 15 yrs | — |
Regional Water Comparison
How Mount Martha compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ Mount Martha, Victoria | 7.5 mg/L | 🟢 Soft | reservoir |
| Mornington, Victoria | 21 mg/L | 🟢 Soft | reservoir |
| Mount Eliza, Victoria | 11.5 mg/L | 🟢 Soft | reservoir |
| Rosebud, Victoria | 109.5 mg/L | 🟡 Moderately Hard | reservoir |
| Frankston South, Victoria | 18 mg/L | 🟢 Soft | reservoir |
National Benchmark
How Mount Martha compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Mount Martha | 7.5 mg/L | 🟢 None |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
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What Makes Mount Martha's Water Unique?
Local geology and source profile
Mount Martha'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 Mount Martha is measured at 7.5 mg/L — classified as extremely soft — among the lowest recorded values for any community in metropolitan Victoria, far below the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. The TDS of 12.1 mg/L — essentially pure water — confirms that Mount Martha receives one of Australia's most mineral-free urban supplies at this prestigious Mornington Peninsula coastal community.
Mount Martha's extraordinarily soft supply reflects a direct Yarra Ranges reservoir supply pathway to the outer southern Mornington Peninsula coast with virtually no Winneke WTP blending. The Thomson and Upper Yarra storages collect rainfall from Devonian granite and rhyodacite — among the most chemically inert formations on Earth — contributing essentially zero dissolved minerals. Mount Martha's position at the southern extremity of Melbourne Water's metropolitan distribution, at the Mornington Peninsula coastal tip adjacent to the Port Phillip Bay beachfront, places it at the very end of a long supply pipeline that delivers the Yarra Ranges' pure softness with minimal additional mineral loading.
Mount Martha residents experience absolutely no limescale accumulation — taps, glass shower screens, and kettles remain permanently scale-free. Hot water systems maintain peak efficiency indefinitely with no scale concerns. At 7.5 mg/L, some residents choose to install a mineralising filter to add trace minerals for improved taste. South East Water provides water quality information at southeastwater.com.au, with all ADWG health standards consistently met. Mount Martha's pure, ultra-soft supply is a remarkable household benefit for this coastal clifftop community overlooking Port Phillip Bay's eastern shores.
Geology & Source: Supplied by South East Water (water retailer) and Melbourne Water (wholesale) from the Thomson Reservoir and Upper Yarra catchment systems — the Mount Martha Mornington Peninsula coastal supply carries essentially pure water at just 7.5 mg/L with TDS of 12.1 mg/L, among the absolute lowest mineral content of any Australian urban community, reflecting near-source Yarra Ranges reservoir supply delivered to the outer southern Mornington Peninsula coast.