Water hardness in Arrentela
141 mg/L hard
Tap water in Arrentela is hard: 141 mg/L (8.2 gpg · 7.9 °dH · 14.1 °fH).
Source: Município do Seixal - Edital 239/2014, qualidade da água 3.º trimestre 2014 (2014) · data checked 2026-10-29
Range across supply zones: 92–190 mg/L.
This figure is over 3 years old; hardness may have changed.
The only published figure for Arrentela is the Seixal municipality's edital 239/2014, with 7 concelho-wide samples from 92 to 190 mg/L CaCO₃. The 141 mg/L shown is the midpoint. This data is from 2014 and is marked as stale, so it may not reflect the supply today. Nearby Seixal zones vary a lot, so a local check is worthwhile.
Portuguese operators report "dureza total" in mg/L CaCO₃ to ERSAR.
Water data
| Total hardness | 141 mg/L |
|---|---|
| Utility | Município do Seixal |
How Arrentela compares
- Tap water in Arrentela is 69 % harder than the median of the 77 cities we track in Portugal (83 mg/L).
- By hardness it ranks 6 of 77 in Portugal (1 = hardest); 93 % of these cities have softer water.
- Nearest city with clearly softer water: Lisbon, 12 km away (63 mg/L).
- Nearest city with clearly harder water: Corroios, 5 km away (232 mg/L).
Ranking of the hardest and softest water in Portugal →
What it means at home
- Fast scale on taps, shower screens and kettle; white spots on glassware.
- Water heater: efficiency loss and element failures within years if unprotected.
- Dry skin and dull hair after showering are common.
- Softener recommended; jug or reverse osmosis for drinking.
How much salt will you use for softening?
Recommended, especially with a heater or boiler: scale cuts efficiency and shortens its life.
Descale a coffee machine or kettle about every 2 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Arrentela
| Brand | Setting for this water |
|---|---|
| Bosch | H01 |
| Miele | 8 °dH |
| AEG / Electrolux | 2 |
| Beko | 3rd |
| Hoover | S1 |
| 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 Arrentela water hard or soft?
It is hard: 141 mg/L as CaCO₃ (8.2 gpg, 7.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Arrentela 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 Arrentela water?
8.2 gpg, equal to 7.9 °dH, 14.1 °fH or 141 mg/L calcium carbonate.
What dishwasher salt setting should I use in Arrentela?
For 141 mg/L (7.9 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Arrentela?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: Município do Seixal - Edital 239/2014, qualidade da água 3.º trimestre 2014 (2014). Method: computed from supplier's calcium and magnesium. Município do Seixal - Edital 239/2014, qualidade da água 3.º trimestre 2014 · Outdated figure? Tell us