Water hardness in Dounan
210 mg/L very hard
Tap water in Dounan is very hard: 210 mg/L (12.3 gpg · 11.8 °dH · 21 °fH).
Source: Taiwan Water Corporation open data (2026) · data checked 2026-10-21
Taiwan Water Corporation's 2026 tap-water data put hardness in Dounan at 210.0 mg/L CaCO₃. Surface water cannot meet demand on the Choshui alluvial fan, so groundwater is an important source here, which tends to carry more dissolved minerals. Water this hard leaves heavy limescale on heating elements and taps and shortens the interval between descaling.
Taiwan Water Corporation reports total hardness in mg/L CaCO₃; the drinking-water standard is 300 mg/L.
Water data
| Total hardness | 210 mg/L |
|---|---|
| Utility | Taiwan Water Corporation |
How Dounan compares
- Tap water in Dounan is 67 % harder than the median of the 265 cities we track in Taiwan (126 mg/L).
- By hardness it ranks 22 of 265 in Taiwan (1 = hardest); 90 % of these cities have softer water.
- In Yunlin County it is number 2 of 17 cities; the regional median is 194 mg/L.
- Nearest city with clearly softer water: Douliu, 8 km away (153 mg/L).
- Nearest city with clearly harder water: Neimen, 82 km away (293 mg/L).
Ranking of the hardest and softest water in Taiwan →
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 Dounan
| Brand | Setting for this water |
|---|---|
| Bosch | H03 |
| Miele | 12 °dH |
| AEG / Electrolux | 3 |
| Beko | 3rd |
| Hoover | S2 |
| LG | H2 |
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 Dounan water hard or soft?
It is very hard: 210 mg/L as CaCO₃ (12.3 gpg, 11.8 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Dounan safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Taiwan Water Corporation reports total hardness in mg/L CaCO₃; the drinking-water standard is 300 mg/L.
How many grains per gallon is Dounan water?
12.3 gpg, equal to 11.8 °dH, 21 °fH or 210 mg/L calcium carbonate.
What dishwasher salt setting should I use in Dounan?
For 210 mg/L (11.8 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Dounan?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Taiwan Water Corporation open data (2026). Method: figure published by the water supplier. Taiwan Water Corporation open data · Outdated figure? Tell us