Water hardness in Suzuka
45 mg/L soft
Tap water in Suzuka is soft: 45 mg/L (2.6 gpg · 2.5 °dH · 4.5 °fH).
Source: Suzuka City Waterworks Department, tap-water quality test results FY2025 (令和7年度 給水栓の水質検査結果) (2025) · data checked 2026-11-05
Range across supply zones: 30–63 mg/L.
Suzuka's FY2025 results come from 18 public-facility taps with twelve monthly readings each. The city does not print an annual mean, so each tap average was computed from its twelve readings and the 44.46 mg/L shown is the median of those averages. Monthly readings range from 30.1 to 63 mg/L. Because the value is computed rather than quoted, it is marked as such, and it may differ slightly from any figure the utility states in other documents.
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 | 45 mg/L |
|---|---|
| Utility | Suzuka City Waterworks Department |
How Suzuka compares
- Tap water in Suzuka is 11 % softer than the median of the 228 cities we track in Japan (50 mg/L).
- By hardness it ranks 138 of 228 in Japan (1 = hardest); 38 % of these cities have softer water.
- Nearest city with clearly softer water: Nagoya, 44 km away (19 mg/L).
- Nearest city with clearly harder water: Katano, 83 km away (56 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 Suzuka
| 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 Suzuka water hard or soft?
It is soft: 45 mg/L as CaCO₃ (2.6 gpg, 2.5 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Suzuka 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 Suzuka water?
2.6 gpg, equal to 2.5 °dH, 4.5 °fH or 45 mg/L calcium carbonate.
What dishwasher salt setting should I use in Suzuka?
For 45 mg/L (2.5 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Suzuka?
No. With soft water a softener adds nothing.
Source
Source: Suzuka City Waterworks Department, tap-water quality test results FY2025 (令和7年度 給水栓の水質検査結果) (2025). Method: computed from supplier's calcium and magnesium. Suzuka City Waterworks Department, tap-water quality test results FY2025 (令和7年度 給水栓の水質検査結果) · Outdated figure? Tell us