Perth Water Quality · Two Rocks
Water quality in Two Rocks
Your local water hardness and the full breakdown of 16 parameters, sourced from Water Corporation's 2024–25 report.
Updated with Water Corporation 2024-25 data.
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Covers: Two Rocks
These figures are about taste, scale and appliance life — not safety. Is Perth tap water safe to drink? →
Two Rocks supply zone
Very hard water
228mg/L total hardness (range 220–240)
Water in Two Rocks is very hard — among the hardest in Perth. Limescale will build up quickly on appliances and hot water systems. Scale prevention is well worth it here.
Other figures worth knowing
Chlorine by-products (THMs)0.005mg/L
pH7.57
Dissolved solids525mg/L
Sodium57mg/L
Perth's water is disinfected with free chlorine at roughly 0.4–1.0 mg/L network-wide. The figure above is trihalomethanes (THMs) — by-products of chlorination that a catalytic carbon filter reduces. In Two Rocks they run at about 2% of the safety guideline.
What this means for your home
Water in Two Rocks is very hard — among the hardest in Perth. Limescale will build up quickly on appliances and hot water systems. Scale prevention is well worth it here.
✓Our honest take: Scale prevention is strongly worth it here — it meaningfully extends the life of your hot water system and appliances.
Full water quality breakdown — Two Rocks
Scale & hardness
Total hardness228220–240 mg/L as CaCO3
Total dissolved solids525518–530 mg/L
Alkalinity195190–200 mg/L as CaCO3
Silica11.310–13 mg/L
General chemistry
pH7.577.54–7.63 pH units
Sodium5755–59 mg/L
Chloride110110–110 mg/L
Sulphate1816–19 mg/L
Aesthetic (taste, colour, staining)
Iron0.0030.003–0.003 mg/L
Manganese0.0020.002–0.002 mg/L
Aluminium0.0080.008–0.008 mg/L
True colour11–1 HU
Turbidity0.10.1–0.2 NTU
Health-related
Fluoride0.150.15–0.15 mg/L
Nitrate4.44.4–4.8 mg/L
Trihalomethanes (THMs)0.0050.001–0.009 mg/L
About this supply area: Water Corporation reports quality by supply locality rather than individual suburb, so the suburbs listed at the top of this page all share the Two Rocks figures. Your exact property may vary slightly. Water Corporation doesn’t publish supply boundaries street-by-street, so matching suburbs to localities involves some interpretation — homes near a boundary may actually be served by a neighbouring locality, and figures there can differ slightly.
Source: Water Corporation Drinking Water Quality Annual Report 2024–25, Perth Region (aesthetic & health tables). Figures are locality means with min–max range. Verified July 2026. Two Rocks met all health-related safety requirements in 2024–25. See all Perth suburbs →