Water hardness in Marinha Grande
74 mg/L moderately hard
Tap water in Marinha Grande is moderately hard: 74 mg/L (4.3 gpg · 4.1 °dH · 7.4 °fH).
Source: Município da Marinha Grande - Relatório trimestral 2.º trimestre 2023 (2023) · data checked 2026-10-29
Range across supply zones: 42–113 mg/L.
The Marinha Grande municipality's Q2 2023 report gives one hardness result in each of five supply zones: 74, 42.1, 84, 113 and 73 mg/L CaCO₃. The 74 mg/L shown is the median, and the zone names could not be read from the report. The data is from 2023 and may have changed. Which zone serves you changes how much scale to expect.
Portuguese operators report "dureza total" in mg/L CaCO₃ to ERSAR.
Water data
| Total hardness | 74 mg/L |
|---|---|
| Utility | Município da Marinha Grande |
How Marinha Grande compares
- Tap water in Marinha Grande is 11 % softer than the median of the 77 cities we track in Portugal (83 mg/L).
- By hardness it ranks 49 of 77 in Portugal (1 = hardest); 37 % of these cities have softer water.
- Nearest city with clearly softer water: Leiria, 11 km away (45 mg/L).
- Nearest city with clearly harder water: Alcabideche, 120 km away (289 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 Marinha Grande
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 4 °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 Marinha Grande water hard or soft?
It is moderately hard: 74 mg/L as CaCO₃ (4.3 gpg, 4.1 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Marinha Grande 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 Marinha Grande water?
4.3 gpg, equal to 4.1 °dH, 7.4 °fH or 74 mg/L calcium carbonate.
What dishwasher salt setting should I use in Marinha Grande?
For 74 mg/L (4.1 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Marinha Grande?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Município da Marinha Grande - Relatório trimestral 2.º trimestre 2023 (2023). Method: figure published by the water supplier. Município da Marinha Grande - Relatório trimestral 2.º trimestre 2023 · Outdated figure? Tell us