Carrum Downs Water Hardness & Quality Report (2026)
Water Hardness
~0–59 mg/L
Softestimated · not lab-verified
Source
reservoir
pH Level
7
neutral = 7.0
Lead
0.005 mg/L
✓ Below action level
TDS
17.6 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 Carrum Downs, your appliances are currently losing 4% efficiency due to mineral buildup.
| Appliance | In Carrum Downs | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8.2 yrs | 8.5 yrs | -4% |
| Washing Machine | 11.5 yrs | 12 yrs | -4% |
| Water Heater | 14.4 yrs | 15 yrs | -4% |
Regional Water Comparison
How Carrum Downs compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ Carrum Downs, Victoria | ≈ 0–59 mg/L | 🟢 Soft | reservoir |
| Seaford, Victoria | ≈ 0–60 mg/L | 🟢 Soft | reservoir |
| Frankston East, Victoria | ≈ 0–60 mg/L | 🟢 Soft | reservoir |
| Frankston, Victoria | ≈ 120–179 mg/L | 🟠 Hard | reservoir |
| Langwarrin, Victoria | ≈ 0–60 mg/L | 🟢 Soft | reservoir |
National Benchmark
How Carrum Downs compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Carrum Downs | ≈ 0–59 mg/L | 🟢 None |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
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What Makes Carrum Downs's Water Unique?
Local geology and source profile
South East Water supplies Carrum Downs (postcode 3201) via the Frankston and Carrum Downs supply zones in southeastern Melbourne. The utility manages a mixed portfolio of surface water from reservoirs and groundwater sources across the Port Phillip region. Treatment includes chlorination for disinfection and fluoridation for dental health. The Carrum Downs area sits within the Port Phillip catchment, underlain by Quaternary alluvial and glacial deposits overlying Tertiary marine sediments and Paleozoic basement rocks.
This geological sequence results in relatively soft water, as the younger sediments and weathered basement contribute minimal dissolved calcium and magnesium minerals compared to older carbonate-rich formations. The Port Phillip catchment's geology, characterized by Quaternary alluvial and glacial deposits over Tertiary marine sediments and Paleozoic basement rocks, is responsible for the water's low mineral content.
As soft water, Carrum Downs' supply requires minimal treatment for hardness-related scale buildup. Appliances such as hot water systems, dishwashers, and washing machines experience minimal mineral deposits. Water softeners are not recommended and are unnecessary for this supply. Residents benefit from reduced soap scum, longer appliance lifespan, and lower detergent requirements. Based on 2026 water quality reports, Carrum Downs achieves a WaterScore of 9.2 out of 10 (excellent). Fluoride measures 0.8 mg/L (within the 0.6–1.1 mg/L recommended range), and chlorine residual is 0.98 mg/L (well below the 5 mg/L ADWG guideline). All three parameters tested fall within Australian Drinking Water Guidelines. Tap water is safe to drink.
Geology & Source: Quaternary alluvial and glacial deposits; Tertiary marine sediments and Paleozoic basement rocks; minimal dissolved minerals result in soft water
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