Water hardness in Coimbra
35 mg/L soft
Tap water in Coimbra is soft: 35 mg/L (2 gpg · 1.9 °dH · 3.5 °fH).
Source: Águas de Coimbra - Controlo de qualidade da água, ZA Boavista, 2º trimestre 2026 (2026) · data checked 2026-10-23
Range across supply zones: 29–40 mg/L.
Águas de Coimbra supplies the city, mainly from the Mondego river. The reported hardness is 34.5 mg/L CaCO₃, with measurements from 29.0 to 40.0 mg/L. Limescale is a minor issue here; a softener is unlikely to be necessary.
Portuguese operators report "dureza total" in mg/L CaCO₃ to ERSAR.
Water data
| Total hardness | 35 mg/L |
|---|---|
| calcio_mg_l | 7.7-10 |
| magnesio_mg_l | 3.0-3.2 |
| Utility | Águas de Coimbra, E.M. |
How Coimbra compares
- Tap water in Coimbra is 59 % softer than the median of the 77 cities we track in Portugal (83 mg/L).
- By hardness it ranks 70 of 77 in Portugal (1 = hardest); 8 % of these cities have softer water.
- Nearest city with clearly softer water: Ovar, 75 km away (20 mg/L).
- Nearest city with clearly harder water: Pombal, 37 km away (46 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 Coimbra
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 2 °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 Coimbra water hard or soft?
It is soft: 35 mg/L as CaCO₃ (2 gpg, 1.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Coimbra 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 Coimbra water?
2 gpg, equal to 1.9 °dH, 3.5 °fH or 35 mg/L calcium carbonate.
What dishwasher salt setting should I use in Coimbra?
For 35 mg/L (1.9 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Coimbra?
No. With soft water a softener adds nothing.
Source
Source: Águas de Coimbra - Controlo de qualidade da água, ZA Boavista, 2º trimestre 2026 (2026). Method: computed from supplier's calcium and magnesium. Águas de Coimbra - Controlo de qualidade da água, ZA Boavista, 2º trimestre 2026 · Outdated figure? Tell us