Water hardness in Yokkaichi
46 mg/L soft
Tap water in Yokkaichi is soft: 46 mg/L (2.7 gpg · 2.5 °dH · 4.5 °fH).
Source: Yokkaichi City Water and Sewerage Bureau, water quality annual report FY2024 (令和6年度 水質年報 概要版), tap tables (2024) · data checked 2026-11-05
Range across supply zones: 19–70 mg/L.
The figure is taken from the city's FY2024 annual water quality report, which lists 18 taps with a maximum, minimum and mean for each. The 45.5 mg/L shown is the median of the tap means, and readings range from 19 to 70 mg/L. With that spread, one part of the city may read noticeably higher or lower than another; the summary report does not explain why. The FY2024 edition was the latest we found, and the report itself prints a tap average close to the median.
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 | 46 mg/L |
|---|---|
| Utility | Yokkaichi City Water and Sewerage Bureau |
How Yokkaichi compares
- Tap water in Yokkaichi is 9 % softer than the median of the 228 cities we track in Japan (50 mg/L).
- By hardness it ranks 133 of 228 in Japan (1 = hardest); 41 % of these cities have softer water.
- Nearest city with clearly softer water: Nagoya, 36 km away (19 mg/L).
- Nearest city with clearly harder water: Shimamoto, 88 km away (83 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 Yokkaichi
| 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 Yokkaichi water hard or soft?
It is soft: 46 mg/L as CaCO₃ (2.7 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 Yokkaichi 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 Yokkaichi water?
2.7 gpg, equal to 2.5 °dH, 4.5 °fH or 46 mg/L calcium carbonate.
What dishwasher salt setting should I use in Yokkaichi?
For 46 mg/L (2.5 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Yokkaichi?
No. With soft water a softener adds nothing.
Source
Source: Yokkaichi City Water and Sewerage Bureau, water quality annual report FY2024 (令和6年度 水質年報 概要版), tap tables (2024). Method: figure published by the water supplier. Yokkaichi City Water and Sewerage Bureau, water quality annual report FY2024 (令和6年度 水質年報 概要版), tap tables · Outdated figure? Tell us