Water hardness in Opera
34.9 °fH very hard
Tap water in Opera is very hard: 34.9 °fH (349 mg/L · 20.4 gpg · 19.5 °dH).
Source: Gruppo CAP, analisi acquedotto (open data), 2025 Q3–2026 Q2 (2026-06) · data checked 2026-10-19
Range across supply zones: 168–379 mg/L.
Gruppo CAP's open data for Opera, from 84 network samples between Q3 2025 and Q2 2026, give a median of 348.9 mg/L CaCO₃. Readings range from 167.5 to 378.8 mg/L, so the water is among the hardest in the Milan belt but varies by location. Hardness is calculated from calcium and magnesium. We have not verified the wells that serve the town, and a softener is worth considering once you know the value at your address.
Italian utilities report °f (French degrees); D.Lgs. 31/2001 recommends 15–50 °f.
Water data
| Total hardness | 34.9 °fH |
|---|
How Opera compares
- Tap water in Opera is 64 % harder than the median of the 629 cities we track in Italy (21.2 °fH).
- By hardness it ranks 46 of 629 in Italy (1 = hardest); 93 % of these cities have softer water.
- In Lombardia it is number 3 of 142 cities; the regional median is 24.9 °fH.
- Nearest city with clearly softer water: Pieve Emanuele, 3 km away (13.6 °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 Opera
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 20 °dH |
| AEG / Electrolux | 5 |
| Beko | 5th |
| Hoover | S3 |
| 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 Opera water hard or soft?
It is very hard: 349 mg/L as CaCO₃ (20.4 gpg, 19.5 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Opera 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 Opera water?
20.4 gpg, equal to 19.5 °dH, 34.9 °fH or 349 mg/L calcium carbonate.
What dishwasher salt setting should I use in Opera?
For 349 mg/L (19.5 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Opera?
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