Water hardness in Trezzano sul Naviglio
25.6 °fH very hard
Tap water in Trezzano sul Naviglio is very hard: 25.6 °fH (256 mg/L · 14.9 gpg · 14.3 °dH).
Source: Gruppo CAP, analisi acquedotto (open data), 2025 Q3–2026 Q2 (2026-06) · data checked 2026-10-19
Range across supply zones: 224–291 mg/L.
Gruppo CAP supplies Trezzano sul Naviglio with groundwater pumped from wells in the Po plain around Milan; part of it needs treatment and the rest enters the network untreated; the alluvial aquifer carries dissolved calcium and magnesium from the sediments. Published analyses give a typical value of 255.7 mg/L CaCO₃, with readings from 223.8 to 291.0 mg/L, 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 | 25.6 °fH |
|---|
How Trezzano sul Naviglio compares
- Tap water in Trezzano sul Naviglio is 20 % harder than the median of the 629 cities we track in Italy (21.2 °fH).
- By hardness it ranks 218 of 629 in Italy (1 = hardest); 65 % of these cities have softer water.
- In Lombardia it is number 63 of 142 cities; the regional median is 24.9 °fH.
- Nearest city with clearly softer water: Assago, 5 km away (19.3 °fH).
- Nearest city with clearly harder water: Opera, 13 km away (34.9 °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 sul Naviglio
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 14 °dH |
| AEG / Electrolux | 3 |
| Beko | 4th |
| Hoover | S2 |
| LG | H3 |
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 sul Naviglio water hard or soft?
It is very hard: 256 mg/L as CaCO₃ (14.9 gpg, 14.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Trezzano sul Naviglio 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 sul Naviglio water?
14.9 gpg, equal to 14.3 °dH, 25.6 °fH or 256 mg/L calcium carbonate.
What dishwasher salt setting should I use in Trezzano sul Naviglio?
For 256 mg/L (14.3 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Trezzano sul Naviglio?
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