Water hardness in San Fernando
19.7 °fH very hard
Tap water in San Fernando is very hard: 19.7 °fH (197 mg/L · 11.5 gpg · 11 °dH).
Source: SINAC, Ministerio de Sanidad — Información de un abastecimiento, municipio 11031 (2026-07) · data checked 2026-10-19
The water comes largely from reservoirs in the Guadalete and Majaceite basins and from local sources. Official analyses put the water at 197 mg/L CaCO₃, very hard. Limestone and sedimentary rock dissolve plenty of calcium and magnesium, hence the high hardness. Scale deposits quickly in kettles, heaters and heating elements; many households fit a softener.
Fuentes españolas usan °fH (grados hidrotimétricos franceses) o mg/L CaCO₃.
Water data
| Total hardness | 19.7 °fH |
|---|
How San Fernando compares
- Tap water in San Fernando is close to the median of the 4988 cities we track in Spain (20.1 °fH).
- By hardness it ranks 2544 of 4988 in Spain (1 = hardest); 49 % of these cities have softer water.
- In Cádiz it is number 31 of 43 cities; the regional median is 21.4 °fH.
- Nearest city with clearly softer water: Trebujena, 48 km away (2.3 °fH).
- Nearest city with clearly harder water: Vejer de la Frontera, 28 km away (29 °fH).
Ranking of the hardest and softest water in Spain →
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 San Fernando
| Brand | Setting for this water |
|---|---|
| Bosch | H03 |
| Miele | 11 °dH |
| AEG / Electrolux | 3 |
| Beko | 3rd |
| 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 San Fernando water hard or soft?
It is very hard: 197 mg/L as CaCO₃ (11.5 gpg, 11 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in San Fernando safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Fuentes españolas usan °fH (grados hidrotimétricos franceses) o mg/L CaCO₃.
How many grains per gallon is San Fernando water?
11.5 gpg, equal to 11 °dH, 19.7 °fH or 197 mg/L calcium carbonate.
What dishwasher salt setting should I use in San Fernando?
For 197 mg/L (11 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in San Fernando?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: SINAC, Ministerio de Sanidad — Información de un abastecimiento, municipio 11031 (2026-07). Method: own measurement. SINAC, Ministerio de Sanidad — Información de un abastecimiento, municipio 11031 · Outdated figure? Tell us