Water hardness in Wonju
110 mg/L moderately hard
Tap water in Wonju is moderately hard: 110 mg/L (6.4 gpg · 6.2 °dH · 11 °fH).
Source: K-water / 강원특별자치도 원주시 via data.go.kr (2025) · data checked 2026-10-20
Range across supply zones: 72–149 mg/L.
Wonju reports a median of 110.2 mg/L CaCO₃ for its treated water in 2025, with plants ranging from 71.5 to 149.0 mg/L. Most of Gangwon's supply comes from mountain streams and dams in the upper Han basin, such as Soyanggang; this utility's own source is not confirmed here. Limescale shows on kettles, taps and shower glass within weeks, which regular descaling handles; a softener is optional. The spread between plants is wide, so check which plant serves your street.
Korean waterworks report hardness (경도) in mg/L CaCO₃; the drinking-water standard is 300 mg/L (1,000 mg/L for some sources).
Water data
| Total hardness | 110 mg/L |
|---|---|
| Utility | Wonju-si (강원특별자치도 원주시) |
How Wonju compares
- Tap water in Wonju is 94 % harder than the median of the 127 cities we track in South Korea (57 mg/L).
- By hardness it ranks 7 of 127 in South Korea (1 = hardest); 95 % of these cities have softer water.
- In Gangwon-do it is number 2 of 17 cities; the regional median is 47 mg/L.
- Nearest city with clearly softer water: Chungju, 38 km away (84 mg/L).
- Nearest city with clearly harder water: Donghae, 108 km away (149 mg/L).
Ranking of the hardest and softest water in South Korea →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Wonju
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 6 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H1 |
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 Wonju water hard or soft?
It is moderately hard: 110 mg/L as CaCO₃ (6.4 gpg, 6.2 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Wonju safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Korean waterworks report hardness (경도) in mg/L CaCO₃; the drinking-water standard is 300 mg/L (1,000 mg/L for some sources).
How many grains per gallon is Wonju water?
6.4 gpg, equal to 6.2 °dH, 11 °fH or 110 mg/L calcium carbonate.
What dishwasher salt setting should I use in Wonju?
For 110 mg/L (6.2 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Wonju?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: K-water / 강원특별자치도 원주시 via data.go.kr (2025). Method: figure published by the water supplier. K-water / 강원특별자치도 원주시 via data.go.kr · Outdated figure? Tell us