Water hardness in Trezzano Rosa
20.7 °fH very hard
Tap water in Trezzano Rosa is very hard: 20.7 °fH (207 mg/L · 12.1 gpg · 11.6 °dH).
Source: Gruppo CAP, analisi acquedotto (open data), 2025 Q3–2026 Q2 (2026-06) · data checked 2026-10-20
Range across supply zones: 175–228 mg/L.
Italian utilities report °f (French degrees); D.Lgs. 31/2001 recommends 15–50 °f.
Water data
| Total hardness | 20.7 °fH |
|---|
How Trezzano Rosa compares
- Tap water in Trezzano Rosa is close to the median of the 629 cities we track in Italy (21.2 °fH).
- By hardness it ranks 332 of 629 in Italy (1 = hardest); 47 % of these cities have softer water.
- In Lombardia it is number 109 of 142 cities; the regional median is 24.9 °fH.
- Nearest city with clearly softer water: San Giuliano Milanese, 26 km away (14.3 °fH).
- Nearest city with clearly harder water: Cambiago, 4 km away (30.5 °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 Trezzano Rosa
| Brand | Setting for this water |
|---|---|
| Bosch | H03 |
| Miele | 12 °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 Trezzano Rosa water hard or soft?
It is very hard: 207 mg/L as CaCO₃ (12.1 gpg, 11.6 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Trezzano Rosa 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 Trezzano Rosa water?
12.1 gpg, equal to 11.6 °dH, 20.7 °fH or 207 mg/L calcium carbonate.
What dishwasher salt setting should I use in Trezzano Rosa?
For 207 mg/L (11.6 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Trezzano Rosa?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Gruppo CAP, analisi acquedotto (open data), 2025 Q3–2026 Q2 (2026-06). Method: computed from supplier's calcium and magnesium. Gruppo CAP, analisi acquedotto (open data), 2025 Q3–2026 Q2 · Outdated figure? Tell us