Water hardness in Japan

Japanese waterworks report hardness (硬度) in mg/L CaCO₃; the standard is 300 mg/L and the target 10–100 mg/L.

Ranking of the hardest and softest water in Japan →

Regions

• Aichi8 · 20 mg/L
• Chiba11 · 76 mg/L
• Fukuoka3 · 45 mg/L
• Fukushima3 · 33 mg/L
• Gunma11 · 51 mg/L
• Hiroshima3 · 20 mg/L
• Hokkaido3 · 32 mg/L
• Hyogo6 · 40 mg/L
• Ibaraki3 · 56 mg/L
• Kagawa16 · 46 mg/L
• Kanagawa12 · 62 mg/L
• Niigata3 · 33 mg/L
• Osaka42 · 42 mg/L
• Saitama9 · 67 mg/L
• Shizuoka4 · 46 mg/L
• Tokyo53 · 62 mg/L

Largest places, hardest first

Every place is listed on its region page.