Water hardness in Oeiras
42 mg/L soft
Tap water in Oeiras is soft: 42 mg/L (2.4 gpg · 2.3 °dH · 4.2 °fH).
Source: SIMAS Oeiras e Amadora - Qualidade da água 1.º trimestre 2026 (2026) · data checked 2026-10-29
Oeiras gets EPAL water delivered in bulk to SIMAS Oeiras e Amadora. The only hardness result in the 2026 reports is one analysis of 41.5 mg/L CaCO₃ in the Q1 2026 report, taken at the delivery point. The Q2 2026 report has no hardness analysis. Soft water like this leaves little scale in kettles and heaters.
Portuguese operators report "dureza total" in mg/L CaCO₃ to ERSAR.
Water data
| Total hardness | 42 mg/L |
|---|---|
| Utility | SIMAS Oeiras e Amadora (água EPAL entregue ao concelho) |
How Oeiras compares
- Tap water in Oeiras is 50 % softer than the median of the 77 cities we track in Portugal (83 mg/L).
- By hardness it ranks 64 of 77 in Portugal (1 = hardest); 11 % of these cities have softer water.
- In Lisboa it is number 8 of 13 cities; the regional median is 50 mg/L.
- Nearest city with clearly softer water: Vila Franca de Xira, 40 km away (15 mg/L).
- Nearest city with clearly harder water: Carcavelos, 1 km away (90 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 Oeiras
| 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 Oeiras water hard or soft?
It is soft: 42 mg/L as CaCO₃ (2.4 gpg, 2.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Oeiras 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 Oeiras water?
2.4 gpg, equal to 2.3 °dH, 4.2 °fH or 42 mg/L calcium carbonate.
What dishwasher salt setting should I use in Oeiras?
For 42 mg/L (2.3 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Oeiras?
No. With soft water a softener adds nothing.
Source
Source: SIMAS Oeiras e Amadora - Qualidade da água 1.º trimestre 2026 (2026). Method: figure published by the water supplier. SIMAS Oeiras e Amadora - Qualidade da água 1.º trimestre 2026 · Outdated figure? Tell us