Kwinana Water Hardness & Quality Report (2026)
Water Hardness
Source
mixed
pH Level
8.1
neutral = 7.0
Lead
0.004 mg/L
✓ Below action level
TDS
567.4 mg/L
Est. Daily Cost
A$0.65
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 Kwinana, your appliances are currently losing 27% efficiency due to mineral buildup.
| Appliance | In Kwinana | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 2.9 yrs | 8.5 yrs | -66% |
| Washing Machine | 6.1 yrs | 12 yrs | -49% |
| Water Heater | 7.4 yrs | 15 yrs | -51% |
Regional Water Comparison
How Kwinana compares to its nearest neighbours
| City | Hardness | Risk | Source |
|---|---|---|---|
| ▶ Kwinana, Western Australia | 204 mg/L | 🔴 Very Hard | mixed |
| Rockingham, Western Australia | 172 mg/L | 🟠 Hard | mixed |
| Rockingham city centre, Western Australia | 149.5 mg/L | 🟠 Hard | mixed |
| Waikiki, Western Australia | 234.5 mg/L | 🔴 Very Hard | mixed |
| Baldivis, Western Australia | 231.5 mg/L | 🔴 Very Hard | mixed |
National Benchmark
How Kwinana compares to the Australia average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Kwinana | 204 mg/L | 🔴 High |
| Australia National Avg | 125 mg/L | 🟠 Moderate |
| Boronia Top Rated | 5 mg/L | 🟢 None |
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What Makes Kwinana's Water Unique?
Local geology and source profile
Kwinana's drinking water is supplied by the Water Corporation via the Integrated Water Supply Scheme (IWSS), blending Gnangara Mound limestone groundwater with desalinated supply from the Kwinana Desalination Plant — located directly within the Kwinana industrial and residential corridor — in Western Australia's southern metropolitan area. Water hardness in Kwinana is measured at 204 mg/L — classified as hard, marginally exceeding the Australian Drinking Water Guidelines (ADWG) aesthetic guideline of 200 mg/L published by NHMRC. The elevated TDS of 567.4 mg/L reflects the highly mineralised groundwater component dominant in the local IWSS supply blend.
Kwinana's hard supply reflects the limestone groundwater character of the Swan Coastal Plain. The Gnangara Mound and Jandakot Mound groundwaters percolate slowly through Tamala Limestone and the Superficial Aquifer — highly porous carbonate terrain where calcium carbonate dissolves readily into groundwater over extended residence periods. Despite the co-location of the Kwinana Desalination Plant, the blend proportioning for the local distribution zone incorporates sufficient limestone groundwater to exceed the ADWG aesthetic threshold, indicating a groundwater-heavy supply mix reaching Kwinana's taps.
Kwinana residents deal with significant limescale accumulation on taps, shower screens, and in kettles — descaling every three to four weeks is common. Solar hot water systems, popular in WA's sunny coastal climate, accumulate scale in collector tubes and storage cylinders; annual professional servicing is strongly recommended. Under WA water restrictions, garden irrigation is limited to two days per week. The elevated lead reading (0.004 mg/L) warrants briefly running the cold tap before use. The Water Corporation provides water quality information at watercorporation.com.au, with all ADWG health standards met.
Geology & Source: Supplied by the Water Corporation via the Integrated Water Supply Scheme from Gnangara Mound limestone groundwater and desalinated supply from the adjacent Kwinana Desalination Plant — despite proximity to the desalination facility, the Kwinana distribution zone carries hard supply at 204 mg/L exceeding the ADWG aesthetic guideline, reflecting the dominant limestone groundwater contribution in the local IWSS blend.