Perth Water Quality · Thomsons Lake
Water quality in Thomsons Lake
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: Anketell, Atwell, Aubin Grove, Banjup, Cockburn Central, Hammond Park, Jandakot, Mandogalup, Success, Thomsons Lake, Treeby, Wandi, Wattleup
These figures are about taste, scale and appliance life — not safety. Is Perth tap water safe to drink? →
Thomsons Lake supply zone
Moderately hard
89mg/L total hardness (range 71–96)
Water in Thomsons Lake is moderately hard. You may notice some scale over time on kettles and shower screens, but it’s manageable. Carbon filtration improves taste; softening is optional.
Other figures worth knowing
Chlorine by-products (THMs)0.054mg/L
pH8.01
Dissolved solids486mg/L
Sodium124mg/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 Thomsons Lake they run at about 22% of the safety guideline.
What this means for your home
Water in Thomsons Lake is moderately hard. You may notice some scale over time on kettles and shower screens, but it’s manageable. Carbon filtration improves taste; softening is optional.
✓Our honest take: A carbon filter improves taste and chlorine; scale prevention is a nice-to-have, not essential.
Full water quality breakdown — Thomsons Lake
Scale & hardness
Total hardness8971–96 mg/L as CaCO3
Total dissolved solids486416–530 mg/L
Alkalinity7764–83 mg/L as CaCO3
Silica4.73.9–5.3 mg/L
General chemistry
pH8.017.96–8.04 pH units
Sodium124110–135 mg/L
Chloride206175–230 mg/L
Sulphate2321–24 mg/L
Aesthetic (taste, colour, staining)
Iron0.0030.003–0.004 mg/L
Manganese0.0020.002–0.003 mg/L
Aluminium0.0080.008–0.008 mg/L
True colour11–1 HU
Turbidity0.10.1–0.2 NTU
Health-related
Fluoride0.820.7–0.9 mg/L
Trihalomethanes (THMs)0.0540.034–0.098 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 Thomsons Lake 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. Thomsons Lake met all health-related safety requirements in 2024–25. See all Perth suburbs →