Water hardness in Guimarães
12 mg/L soft
Tap water in Guimarães is soft: 12 mg/L (0.7 gpg · 0.6 °dH · 1.2 °fH).
Source: Vimágua - Relatório de controlo da qualidade da água, Sistema Vimágua, 2º trimestre 2026 (2026) · data checked 2026-10-23
Range across supply zones: 3–20 mg/L.
Guimarães is supplied by its local water utility. Northern and central Portugal sit largely on granite and schist, which gives soft water, while limestone in the south and centre makes it harder. The reported hardness is 11.6 mg/L CaCO₃, with measurements from 2.9 to 20.3 mg/L. Scale builds up slowly, so a softener is rarely needed.
Portuguese operators report "dureza total" in mg/L CaCO₃ to ERSAR.
Water data
| Total hardness | 12 mg/L |
|---|---|
| Utility | Vimágua |
How Guimarães compares
- Tap water in Guimarães is 86 % softer than the median of the 77 cities we track in Portugal (83 mg/L).
- By hardness it ranks 77 of 77 in Portugal (1 = hardest); 0 % of these cities have softer water.
- Nearest city with clearly harder water: Felgueiras, 12 km away (94 mg/L).
Ranking of the hardest and softest water in Portugal →
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 Guimarães
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 1 °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 Guimarães water hard or soft?
It is soft: 12 mg/L as CaCO₃ (0.7 gpg, 0.6 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Guimarães safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Portuguese operators report "dureza total" in mg/L CaCO₃ to ERSAR.
How many grains per gallon is Guimarães water?
0.7 gpg, equal to 0.6 °dH, 1.2 °fH or 12 mg/L calcium carbonate.
What dishwasher salt setting should I use in Guimarães?
For 12 mg/L (0.6 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Guimarães?
No. With soft water a softener adds nothing.
Source
Source: Vimágua - Relatório de controlo da qualidade da água, Sistema Vimágua, 2º trimestre 2026 (2026). Method: computed from supplier's calcium and magnesium. Vimágua - Relatório de controlo da qualidade da água, Sistema Vimágua, 2º trimestre 2026 · Outdated figure? Tell us