Water hardness in Daejeon
53 mg/L soft
Tap water in Daejeon is soft: 53 mg/L (3.1 gpg · 2.9 °dH · 5.3 °fH).
Source: K-water / 대전광역시 via data.go.kr (2025) · data checked 2026-10-20
Range across supply zones: 52–53 mg/L.
Statutory tests of treated water in Daejeon give 52.5 mg/L CaCO₃ as the 2025 median, with plants ranging from 52.0 to 53.0 mg/L. This area belongs to the Geum River basin, where Daecheong Dam supplies water; the utility's own raw-water source is not confirmed here. Limescale is a minor issue at this level, mostly a thin film on kettles and shower glass.
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 | 53 mg/L |
|---|---|
| Utility | Daejeon (대전광역시) |
How Daejeon compares
- Tap water in Daejeon is 8 % softer than the median of the 127 cities we track in South Korea (57 mg/L).
- By hardness it ranks 70 of 127 in South Korea (1 = hardest); 45 % of these cities have softer water.
- Nearest city with clearly softer water: Yeongdong, 40 km away (39 mg/L).
- Nearest city with clearly harder water: Gongju, 26 km away (66 mg/L).
Ranking of the hardest and softest water in South Korea →
What it means at home
- Little or no limescale in kettles, water heaters or washing machines.
- Soap lathers easily; water does not dry skin or hair.
- Dishwasher: salt setting at minimum or off.
- No softener needed; a jug filter only changes taste.
How much salt will you use for softening?
No. Water this soft does not need softening.
Descale a coffee machine or kettle about every 6 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Daejeon
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 3 °dH |
| AEG / Electrolux | 1 |
| Beko | 1st |
| Hoover | S0 |
| LG | H0 |
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 Daejeon water hard or soft?
It is soft: 53 mg/L as CaCO₃ (3.1 gpg, 2.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Daejeon 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 Daejeon water?
3.1 gpg, equal to 2.9 °dH, 5.3 °fH or 53 mg/L calcium carbonate.
What dishwasher salt setting should I use in Daejeon?
For 53 mg/L (2.9 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Daejeon?
No. With soft water a softener adds nothing.
Source
Source: K-water / 대전광역시 via data.go.kr (2025). Method: figure published by the water supplier. K-water / 대전광역시 via data.go.kr · Outdated figure? Tell us