Water hardness in Grass Patch
358 mg/L very hard
Tap water in Grass Patch is very hard: 358 mg/L (20.9 gpg · 20.1 °dH · 35.8 °fH).
Source: Water Corporation, Drinking Water Quality Annual Report, aesthetic tables (great-southern), year to 2025-06 (2025-06) · data checked 2026-10-20
Range across supply zones: 340–380 mg/L.
Australian Drinking Water Guidelines: aesthetic target ≤ 200 mg/L CaCO₃.
Water data
| Total hardness | 358 mg/L |
|---|---|
| Utility | Water Corporation |
How Grass Patch compares
- Tap water in Grass Patch is 321 % harder than the median of the 307 cities we track in Australia (85 mg/L).
- By hardness it ranks 1 of 307 in Australia (1 = hardest); 100 % of these cities have softer water.
- In Western Australia it is number 1 of 218 cities; the regional median is 98 mg/L.
- Nearest city with clearly softer water: Gibson, 47 km away (42 mg/L).
Ranking of the hardest and softest water in Australia →
What it means at home
- Severe scale: heater elements and washing-machine heaters fail early.
- Detergent use is very high; taps and screens coat within days.
- Dishwasher at maximum salt setting.
- An ion-exchange softener is practically essential; RO for drinking water.
How much salt will you use for softening?
Yes. At this hardness a softener pays for itself through appliance life and detergent.
Descale a coffee machine or kettle about every 1 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Grass Patch
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 20 °dH |
| AEG / Electrolux | 5 |
| Beko | 6th |
| Hoover | S3 |
| LG | H3 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is Grass Patch water hard or soft?
It is very hard: 358 mg/L as CaCO₃ (20.9 gpg, 20.1 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Grass Patch safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Australian Drinking Water Guidelines: aesthetic target ≤ 200 mg/L CaCO₃.
How many grains per gallon is Grass Patch water?
20.9 gpg, equal to 20.1 °dH, 35.8 °fH or 358 mg/L calcium carbonate.
What dishwasher salt setting should I use in Grass Patch?
For 358 mg/L (20.1 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Grass Patch?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Water Corporation, Drinking Water Quality Annual Report, aesthetic tables (great-southern), year to 2025-06 (2025-06). Method: figure published by the water supplier. Water Corporation, Drinking Water Quality Annual Report, aesthetic tables (great-southern), year to 2025-06 · Outdated figure? Tell us