Water hardness in Kobe
39 mg/L soft
Tap water in Kobe is soft: 39 mg/L (2.3 gpg · 2.2 °dH · 3.9 °fH).
Source: Kobe City Waterworks Bureau, monthly water quality results FY2025 (2025) · data checked 2026-10-21
Range across supply zones: 27–50 mg/L.
Kobe buys roughly three quarters of its water from the Hanshin Water Supply Authority, which treats Yodo River and Lake Biwa water, and covers the rest from its own Nunobiki, Karasuhara and Senzari reservoirs. Hardness is reported at 39.0 mg/L CaCO₃, ranging from 26.7 to 50.2 mg/L (2025 data). Scale builds slowly at this level; a light white film on kettles and taps is possible, and a softener is rarely needed.
Japanese waterworks report hardness (硬度) in mg/L CaCO₃; the standard is 300 mg/L and the target 10–100 mg/L.
Water data
| Total hardness | 39 mg/L |
|---|---|
| Utility | Kobe City Waterworks Bureau |
How Kobe compares
- Tap water in Kobe is 22 % softer than the median of the 228 cities we track in Japan (50 mg/L).
- By hardness it ranks 175 of 228 in Japan (1 = hardest); 22 % of these cities have softer water.
- In Hyogo it is number 4 of 6 cities; the regional median is 40 mg/L.
- Nearest city with clearly softer water: Misaki, 43 km away (31 mg/L).
- Nearest city with clearly harder water: Akashi, 17 km away (64 mg/L).
Ranking of the hardest and softest water in Japan →
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 Kobe
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 2 °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 Kobe water hard or soft?
It is soft: 39 mg/L as CaCO₃ (2.3 gpg, 2.2 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Kobe safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Japanese waterworks report hardness (硬度) in mg/L CaCO₃; the standard is 300 mg/L and the target 10–100 mg/L.
How many grains per gallon is Kobe water?
2.3 gpg, equal to 2.2 °dH, 3.9 °fH or 39 mg/L calcium carbonate.
What dishwasher salt setting should I use in Kobe?
For 39 mg/L (2.2 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Kobe?
No. With soft water a softener adds nothing.
Source
Source: Kobe City Waterworks Bureau, monthly water quality results FY2025 (2025). Method: figure published by the water supplier. Kobe City Waterworks Bureau, monthly water quality results FY2025 · Outdated figure? Tell us