Water hardness in Sasebo
46 mg/L soft
Tap water in Sasebo is soft: 46 mg/L (2.7 gpg · 2.5 °dH · 4.5 °fH).
Source: Sasebo City Waterworks Bureau, water quality test annual report FY2025 (令和7年度 水質検査年報 全地区), tap sheets (2025) · data checked 2026-11-05
Range across supply zones: 14–181 mg/L.
Sasebo's FY2025 annual report has sheets for 28 taps in seven areas, including Sasebo proper, Yoshii, Sechibaru, Kosasa, Uku, Eto and Shikamachi. The 45.5 mg/L shown is the median of the 28 tap averages, while individual readings range from 14 to 181 mg/L, a very wide spread. The highest readings come from a minority of taps, and the published sheets do not explain why. For a specific address, find the nearest tap in the report before relying on the city-wide figure.
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 | Sasebo City Waterworks Bureau |
How Sasebo compares
- Tap water in Sasebo 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: Nagasaki, 49 km away (25 mg/L).
- Nearest city with clearly harder water: Kumamoto, 99 km away (70 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 Sasebo
| 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 Sasebo 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 Sasebo 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 Sasebo 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 Sasebo?
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 Sasebo?
No. With soft water a softener adds nothing.
Source
Source: Sasebo City Waterworks Bureau, water quality test annual report FY2025 (令和7年度 水質検査年報 全地区), tap sheets (2025). Method: figure published by the water supplier. Sasebo City Waterworks Bureau, water quality test annual report FY2025 (令和7年度 水質検査年報 全地区), tap sheets · Outdated figure? Tell us