Water hardness in Lisbon
63 mg/L moderately hard
Tap water in Lisbon is moderately hard: 63 mg/L (3.7 gpg · 3.5 °dH · 6.3 °fH).
Source: EPAL — Qualidade da água para consumo humano, torneiras do consumidor, rede de distribuição da cidade de Lisboa, 2.º trimestre 2026 (2026-08) · data checked 2026-10-23
Range across supply zones: 50–76 mg/L.
EPAL's main source is the Castelo do Bode reservoir on the Zêzere, supplemented by the Tagus intake at Valada, springs at Alviela and some boreholes. The reported hardness is 63.2 mg/L CaCO₃, with measurements from 50.3 to 76.2 mg/L. Expect light scale on taps and kettles; most homes manage with descaling.
Portuguese operators report "dureza total" in mg/L CaCO₃ to ERSAR.
Water data
| Total hardness | 63 mg/L |
|---|---|
| Utility | EPAL |
How Lisbon compares
- Tap water in Lisbon is 24 % softer than the median of the 77 cities we track in Portugal (83 mg/L).
- By hardness it ranks 51 of 77 in Portugal (1 = hardest); 34 % of these cities have softer water.
- In 14 it is number 12 of 19 cities; the regional median is 75 mg/L.
- Nearest city with clearly softer water: Alfornelos, 6 km away (42 mg/L).
- Nearest city with clearly harder water: Alvalade, 3 km away (80 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 Lisbon
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 4 °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 Lisbon water hard or soft?
It is moderately hard: 63 mg/L as CaCO₃ (3.7 gpg, 3.5 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Lisbon 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 Lisbon water?
3.7 gpg, equal to 3.5 °dH, 6.3 °fH or 63 mg/L calcium carbonate.
What dishwasher salt setting should I use in Lisbon?
For 63 mg/L (3.5 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Lisbon?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: EPAL — Qualidade da água para consumo humano, torneiras do consumidor, rede de distribuição da cidade de Lisboa, 2.º trimestre 2026 (2026-08). Method: computed from supplier's calcium and magnesium. EPAL — Qualidade da água para consumo humano, torneiras do consumidor, rede de distribuição da cidade de Lisboa, 2.º trimestre 2026 · Outdated figure? Tell us