Water hardness in Fontana (California)
8.3 gpg hard
Tap water in Fontana (California) is hard: 8.3 gpg (143 mg/L · 8 °dH · 14.3 °fH).
Source: Fontana Water Company 2025 Consumer Confidence Report (CPUC copy) (2025) · data checked 2026-10-19
Range across supply zones: 98–187 mg/L.
2 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| gpg | mg/L | ||
|---|---|---|---|
| groundwater sources (Chino Rialto Lytle basins) | 8.8 | 151 | hard |
| surface water (Summit Water Treatment Plant) | 7.8 | 134 | hard |
Fontana Water Company's 2025 report separates two sources. Groundwater averages 151 mg/L (97.8 to 187) and treated surface water from the Summit plant averages 134 mg/L (106 to 162). The page shows 142.7 mg/L (8.3 gpg), the median of the two. Both are hard, so scale is likely.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 8.3 gpg |
|---|---|
| Utility | Fontana Water Company (CPUC regulated) |
How Fontana (California) compares
- Tap water in Fontana (California) is 8 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 753 of 1372 in the United States (1 = hardest); 45 % of these cities have softer water.
- In California it is number 199 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Moreno Valley, 25 km away (5.1 gpg).
- Nearest city with clearly harder water: Colton, 11 km away (12 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 Fontana
| Brand | Setting for this water |
|---|---|
| Bosch | H01 |
| Miele | 8 °dH |
| AEG / Electrolux | 2 |
| Beko | 3rd |
| 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 Fontana (California) water hard or soft?
It is hard: 143 mg/L as CaCO₃ (8.3 gpg, 8 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Fontana (California) 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 Fontana (California) water?
8.3 gpg, equal to 8 °dH, 14.3 °fH or 143 mg/L calcium carbonate.
What dishwasher salt setting should I use in Fontana (California)?
For 143 mg/L (8 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Fontana (California)?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: Fontana Water Company 2025 Consumer Confidence Report (CPUC copy) (2025). Method: figure published by the water supplier. Fontana Water Company 2025 Consumer Confidence Report (CPUC copy) · Outdated figure? Tell us