Water hardness in Erba
22 °fH very hard
Tap water in Erba is very hard: 22 °fH (220 mg/L · 12.9 gpg · 12.3 °dH).
Source: Como Acqua - Dati qualità dell acqua (aggiornati al 31 agosto 2026) (2026) · data checked 2026-10-29
Range across supply zones: 210–270 mg/L.
4 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| °fH | mg/L | ||
|---|---|---|---|
| Fontana P.zza Mercato | 22 | 220 | very hard |
| Fontana Via Campolasso | 22 | 220 | very hard |
| Fontana Via Minoretti | 21 | 210 | very hard |
| Fontana Via Puccini | 27 | 270 | very hard |
Como Acqua's data, updated to 31 August 2026, record a measured hardness of 220 mg/L CaCO₃ (22 °f) for Erba, with a range of 210 to 270 mg/L (21 to 27 °f). The water is very hard. Expect visible scale on kettles and shower screens.
Italian utilities report °f (French degrees); D.Lgs. 31/2001 recommends 15–50 °f.
Water data
| Total hardness | 22 °fH |
|---|---|
| ca_mg_l | 87 |
| mg_mg_l | 12 |
| Utility | Como Acqua Srl |
How Erba compares
- Tap water in Erba is close to the median of the 629 cities we track in Italy (21.2 °fH).
- By hardness it ranks 298 of 629 in Italy (1 = hardest); 52 % of these cities have softer water.
- In Lombardia it is number 96 of 142 cities; the regional median is 24.9 °fH.
- Nearest city with clearly softer water: Mariano Comense, 13 km away (17 °fH).
- Nearest city with clearly harder water: Cantù, 11 km away (32 °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 Erba
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| 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 Erba water hard or soft?
It is very hard: 220 mg/L as CaCO₃ (12.9 gpg, 12.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Erba 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 Erba water?
12.9 gpg, equal to 12.3 °dH, 22 °fH or 220 mg/L calcium carbonate.
What dishwasher salt setting should I use in Erba?
For 220 mg/L (12.3 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Erba?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Como Acqua - Dati qualità dell acqua (aggiornati al 31 agosto 2026) (2026). Method: own measurement. Como Acqua - Dati qualità dell acqua (aggiornati al 31 agosto 2026) · Outdated figure? Tell us