Water hardness in Toyama
56 mg/L soft
Tap water in Toyama is soft: 56 mg/L (3.3 gpg · 3.1 °dH · 5.6 °fH).
Source: Toyama City Waterworks and Sewerage Bureau (富山市上下水道局), water quality annual report FY2025 (2025) · data checked 2026-10-21
Range across supply zones: 15–141 mg/L.
Toyama operates around 45 treatment sites, with surface water from the Jōganji River at its largest plant and groundwater, riverbed water and springs elsewhere. The reported figure is 56.0 mg/L CaCO₃ (range 14.8 to 141.2 mg/L, 2025 data); the spread is wide, so the value at your tap depends on where in the supply area you live. Moderately soft water leaves visible deposits on kettles and taps over time, which regular descaling keeps in check.
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 | 56 mg/L |
|---|---|
| Utility | Toyama City Waterworks and Sewerage Bureau (富山市上下水道局) |
How Toyama compares
- Tap water in Toyama is 12 % harder than the median of the 228 cities we track in Japan (50 mg/L).
- By hardness it ranks 96 of 228 in Japan (1 = hardest); 56 % of these cities have softer water.
- Nearest city with clearly softer water: Kanazawa, 55 km away (23 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 Toyama
| 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 Toyama water hard or soft?
It is soft: 56 mg/L as CaCO₃ (3.3 gpg, 3.1 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Toyama 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 Toyama water?
3.3 gpg, equal to 3.1 °dH, 5.6 °fH or 56 mg/L calcium carbonate.
What dishwasher salt setting should I use in Toyama?
For 56 mg/L (3.1 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Toyama?
No. With soft water a softener adds nothing.
Source
Source: Toyama City Waterworks and Sewerage Bureau (富山市上下水道局), water quality annual report FY2025 (2025). Method: figure published by the water supplier. Toyama City Waterworks and Sewerage Bureau (富山市上下水道局), water quality annual report FY2025 · Outdated figure? Tell us