Water hardness in Siena
23 °fH very hard
Tap water in Siena is very hard: 23 °fH (230 mg/L · 13.4 gpg · 12.9 °dH).
Source: Acquedotto del Fiora, qualità dell'acqua (analisi per zona di fornitura, 1° semestre 2026) (2026-06) · data checked 2026-10-29
Acquedotto del Fiora supplies Siena as part of its Grosseto and Siena service area; its historic core is the group of springs on Monte Amiata at Santa Fiora; we have not verified which source reaches Siena directly. The utility reports 230.0 mg/L CaCO₃, which counts as very hard water. Expect scale on kettles, shower heads and in the water heater, and descaling about as often as a hard-water kitchen requires.
Italian utilities report °f (French degrees); D.Lgs. 31/2001 recommends 15–50 °f.
Water data
| Total hardness | 23 °fH |
|---|---|
| calcio_mg_l | 65.4 |
| magnesio_mg_l | 15 |
| Utility | Acquedotto del Fiora |
How Siena compares
- Tap water in Siena is 8 % harder than the median of the 629 cities we track in Italy (21.2 °fH).
- By hardness it ranks 276 of 629 in Italy (1 = hardest); 56 % of these cities have softer water.
- In Toscana it is number 5 of 9 cities; the regional median is 23 °fH.
- Nearest city with clearly softer water: Follonica, 63 km away (12 °fH).
- Nearest city with clearly harder water: Colle di Val d'Elsa, 20 km away (36 °fH).
Ranking of the hardest and softest water in Italy →
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 Siena
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 13 °dH |
| AEG / Electrolux | 3 |
| Beko | 4th |
| 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 Siena water hard or soft?
It is very hard: 230 mg/L as CaCO₃ (13.4 gpg, 12.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Siena safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Italian utilities report °f (French degrees); D.Lgs. 31/2001 recommends 15–50 °f.
How many grains per gallon is Siena water?
13.4 gpg, equal to 12.9 °dH, 23 °fH or 230 mg/L calcium carbonate.
What dishwasher salt setting should I use in Siena?
For 230 mg/L (12.9 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Siena?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Acquedotto del Fiora, qualità dell'acqua (analisi per zona di fornitura, 1° semestre 2026) (2026-06). Method: figure published by the water supplier. Acquedotto del Fiora, qualità dell'acqua (analisi per zona di fornitura, 1° semestre 2026) · Outdated figure? Tell us