Water hardness in Corroios
232 mg/L very hard
Tap water in Corroios is very hard: 232 mg/L (13.6 gpg · 13 °dH · 23.2 °fH).
Source: Câmara Municipal do Seixal - Classificação da Dureza da Água no Município do Seixal (2024) (2024) · data checked 2026-10-22
Range across supply zones: 213–251 mg/L.
2 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| mg/L | mg/L | ||
|---|---|---|---|
| Belverde (Verdizela) | 213 | 213 | very hard |
| Santa Marta | 251 | 251 | very hard |
Corroios 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 figure shown, 232.0 mg/L CaCO₃, is the median across 2 supply zones, which range from 213.0 to 251.0 mg/L, so it depends on which zone your street is in. Scale forms fast on heaters and fittings; a water softener is a common remedy.
Portuguese operators report "dureza total" in mg/L CaCO₃ to ERSAR.
Water data
| Total hardness | 232 mg/L |
|---|---|
| Utility | Câmara Municipal do Seixal (municipal water management) |
How Corroios compares
- Tap water in Corroios is 179 % harder than the median of the 77 cities we track in Portugal (83 mg/L).
- By hardness it ranks 2 of 77 in Portugal (1 = hardest); 99 % of these cities have softer water.
- In 19 it is number 1 of 4 cities; the regional median is 158 mg/L.
- Nearest city with clearly softer water: Amora, 3 km away (166 mg/L).
Ranking of the hardest and softest water in Portugal →
What it means at home
- Severe scale: heater elements and washing-machine heaters fail early.
- Detergent use is very high; taps and screens coat within days.
- Dishwasher at maximum salt setting.
- An ion-exchange softener is practically essential; RO for drinking water.
How much salt will you use for softening?
Yes. At this hardness a softener pays for itself through appliance life and detergent.
Descale a coffee machine or kettle about every 1 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Corroios
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 13 °dH |
| AEG / Electrolux | 3 |
| Beko | 4th |
| Hoover | S2 |
| LG | H2 |
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 Corroios water hard or soft?
It is very hard: 232 mg/L as CaCO₃ (13.6 gpg, 13 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Corroios 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 Corroios water?
13.6 gpg, equal to 13 °dH, 23.2 °fH or 232 mg/L calcium carbonate.
What dishwasher salt setting should I use in Corroios?
For 232 mg/L (13 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Corroios?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Câmara Municipal do Seixal - Classificação da Dureza da Água no Município do Seixal (2024) (2024). Method: figure published by the water supplier. Câmara Municipal do Seixal - Classificação da Dureza da Água no Município do Seixal (2024) · Outdated figure? Tell us