Water hardness in Rancho Cucamonga
7.3 gpg hard
Tap water in Rancho Cucamonga is hard: 7.3 gpg (126 mg/L · 7 °dH · 12.6 °fH).
Source: Cucamonga Valley Water District 2025 Water Quality Report (2025) · data checked 2026-10-19
Range across supply zones: 109–142 mg/L.
Cucamonga Valley Water District's 2025 water quality report lists total hardness as CaCO3 at an average of 125.5 mg/L (7.3 gpg), with detected values from 109 to 142 mg/L. That is hard water, and the report gives one district-wide figure with no zone split. We did not confirm the data year on the report cover. Expect visible scale on kettles and water heaters.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 7.3 gpg |
|---|---|
| Utility | Cucamonga Valley Water District (CVWD) |
How Rancho Cucamonga compares
- Tap water in Rancho Cucamonga is 19 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 861 of 1372 in the United States (1 = hardest); 37 % of these cities have softer water.
- In California it is number 222 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Moreno Valley, 37 km away (5.1 gpg).
- Nearest city with clearly harder water: Upland, 9 km away (10.2 gpg).
Ranking of the hardest and softest water in the United States →
What it means at home
- Fast scale on taps, shower screens and kettle; white spots on glassware.
- Water heater: efficiency loss and element failures within years if unprotected.
- Dry skin and dull hair after showering are common.
- Softener recommended; jug or reverse osmosis for drinking.
How much salt will you use for softening?
Recommended, especially with a heater or boiler: scale cuts efficiency and shortens its life.
Descale a coffee machine or kettle about every 2 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Rancho Cucamonga
| Brand | Setting for this water |
|---|---|
| Bosch | H01 |
| Miele | 7 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| 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 Rancho Cucamonga water hard or soft?
It is hard: 126 mg/L as CaCO₃ (7.3 gpg, 7 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Rancho Cucamonga safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
How many grains per gallon is Rancho Cucamonga water?
7.3 gpg, equal to 7 °dH, 12.6 °fH or 126 mg/L calcium carbonate.
What dishwasher salt setting should I use in Rancho Cucamonga?
For 126 mg/L (7 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Rancho Cucamonga?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: Cucamonga Valley Water District 2025 Water Quality Report (2025). Method: own measurement. Cucamonga Valley Water District 2025 Water Quality Report · Outdated figure? Tell us