Water hardness in Gondomar
83 mg/L moderately hard
Tap water in Gondomar is moderately hard: 83 mg/L (4.9 gpg · 4.7 °dH · 8.3 °fH).
Source: ADP - Qualidade da água para consumo humano, 2.º trimestre 2026 (Gondomar) (2026-08) · data checked 2026-10-29
Range across supply zones: 53–109 mg/L.
3 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| mg/L | mg/L | ||
|---|---|---|---|
| ADP Gondomar | 109 | 109 | moderately hard |
| ADP Gondomar Paiva | 53 | 53 | soft |
| UF Gondomar (São Cosme), Valbom e Jovim | 83 | 83 | moderately hard |
Gondomar has more than one source. ADP's Q2 2026 reports show two bulk deliveries, one analysis each, at 53 and 109 mg/L CaCO₃. Águas de Gondomar reports 68 to 94 mg/L for the Gondomar (São Cosme), Valbom and Jovim parishes, with a mean of 83.3 mg/L; its table gives no period. The figure shown depends on which supply feeds your street, so check the utility.
Portuguese operators report "dureza total" in mg/L CaCO₃ to ERSAR.
Water data
| Total hardness | 83 mg/L |
|---|---|
| Utility | Águas do Douro e Paiva (ADP), concelho Gondomar |
How Gondomar compares
- Tap water in Gondomar is close to the median of the 77 cities we track in Portugal (83 mg/L).
- By hardness it ranks 39 of 77 in Portugal (1 = hardest); 50 % of these cities have softer water.
- In Porto it is number 12 of 14 cities; the regional median is 98 mg/L.
- Nearest city with clearly softer water: Penafiel, 22 km away (55 mg/L).
- Nearest city with clearly harder water: Espinho, 18 km away (122 mg/L).
Ranking of the hardest and softest water in Portugal →
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 Gondomar
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 5 °dH |
| AEG / Electrolux | 2 |
| Beko | 1st |
| 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 Gondomar water hard or soft?
It is moderately hard: 83 mg/L as CaCO₃ (4.9 gpg, 4.7 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Gondomar 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 Gondomar water?
4.9 gpg, equal to 4.7 °dH, 8.3 °fH or 83 mg/L calcium carbonate.
What dishwasher salt setting should I use in Gondomar?
For 83 mg/L (4.7 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Gondomar?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: ADP - Qualidade da água para consumo humano, 2.º trimestre 2026 (Gondomar) (2026-08). Method: figure published by the water supplier. ADP - Qualidade da água para consumo humano, 2.º trimestre 2026 (Gondomar) · Outdated figure? Tell us