Water hardness in Longtan
86 mg/L moderately hard
Tap water in Longtan is moderately hard: 86 mg/L (5 gpg · 4.8 °dH · 8.6 °fH).
Source: Taiwan Water Corporation open data (2026) · data checked 2026-10-20
Taiwan Water Corporation's 2026 tap-water data put hardness in Longtan at 86.4 mg/L CaCO₃. Taoyuan is supplied largely from the Dahan River via Shimen Reservoir and its channels. At this level a white film forms on kettles and shower screens, and water heaters collect scale slowly over the years.
Taiwan Water Corporation reports total hardness in mg/L CaCO₃; the drinking-water standard is 300 mg/L.
Water data
| Total hardness | 86 mg/L |
|---|---|
| Utility | Taiwan Water Corporation |
How Longtan compares
- Tap water in Longtan is 31 % softer than the median of the 265 cities we track in Taiwan (126 mg/L).
- By hardness it ranks 212 of 265 in Taiwan (1 = hardest); 20 % of these cities have softer water.
- In Taoyuan it is number 9 of 11 cities; the regional median is 91 mg/L.
- Nearest city with clearly softer water: Fuxing, 15 km away (51 mg/L).
- Nearest city with clearly harder water: Guanxi, 9 km away (124 mg/L).
Ranking of the hardest and softest water in Taiwan →
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 Longtan
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 5 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H1 |
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 Longtan water hard or soft?
It is moderately hard: 86 mg/L as CaCO₃ (5 gpg, 4.8 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Longtan safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Taiwan Water Corporation reports total hardness in mg/L CaCO₃; the drinking-water standard is 300 mg/L.
How many grains per gallon is Longtan water?
5 gpg, equal to 4.8 °dH, 8.6 °fH or 86 mg/L calcium carbonate.
What dishwasher salt setting should I use in Longtan?
For 86 mg/L (4.8 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Longtan?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Taiwan Water Corporation open data (2026). Method: figure published by the water supplier. Taiwan Water Corporation open data · Outdated figure? Tell us