Water hardness in Fujiidera
66 mg/L moderately hard
Tap water in Fujiidera is moderately hard: 66 mg/L (3.9 gpg · 3.7 °dH · 6.6 °fH).
Source: Osaka Water Supply Authority, Fujiidera water service (大阪広域水道企業団 藤井寺水道事業), via Osaka Prefecture 「大阪府の水道の現況」 FY2024 water quality tables (2024) · data checked 2026-10-21
Range across supply zones: 36–74 mg/L.
Fujiidera's water service is run by the Osaka Water Supply Authority, whose supply is Yodo River water treated at its Murano, Niwakubo and Mishima plants; local sources may also contribute, which is not confirmed here. Hardness is reported at 66.0 mg/L CaCO₃, ranging from 36.0 to 74.0 mg/L (2024 data). Expect gradual white deposits on kettles, taps and showerheads; descaling now and then with citric acid is usually enough.
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 | 66 mg/L |
|---|---|
| Utility | Osaka Water Supply Authority, Fujiidera water service (大阪広域水道企業団 藤井寺水道事業) |
How Fujiidera compares
- Tap water in Fujiidera is 31 % harder than the median of the 228 cities we track in Japan (50 mg/L).
- By hardness it ranks 43 of 228 in Japan (1 = hardest); 81 % of these cities have softer water.
- In Osaka it is number 5 of 42 cities; the regional median is 42 mg/L.
- Nearest city with clearly softer water: Matsubara, 4 km away (37 mg/L).
- Nearest city with clearly harder water: Habikino, 2 km away (86 mg/L).
Ranking of the hardest and softest water in Japan →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Fujiidera
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 4 °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 Fujiidera water hard or soft?
It is moderately hard: 66 mg/L as CaCO₃ (3.9 gpg, 3.7 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Fujiidera 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 Fujiidera water?
3.9 gpg, equal to 3.7 °dH, 6.6 °fH or 66 mg/L calcium carbonate.
What dishwasher salt setting should I use in Fujiidera?
For 66 mg/L (3.7 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Fujiidera?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Osaka Water Supply Authority, Fujiidera water service (大阪広域水道企業団 藤井寺水道事業), via Osaka Prefecture 「大阪府の水道の現況」 FY2024 water quality tables (2024). Method: figure published by the water supplier. Osaka Water Supply Authority, Fujiidera water service (大阪広域水道企業団 藤井寺水道事業), via Osaka Prefecture 「大阪府の水道の現況」 FY2024 water quality tables · Outdated figure? Tell us