Water hardness in Oroville
7.6 gpg hard
Tap water in Oroville is hard: 7.6 gpg (130 mg/L · 7.3 °dH · 13 °fH).
Source: California SWRCB Division of Drinking Water, EDT lab results, system CA0410005 (2025-04) · data checked 2026-10-19
Range across supply zones: 36–150 mg/L.
The figure is for California Water Service in Oroville, from State Water Resources Control Board lab results. The median of 9 results from 2021 to 2025, taken at 4 points, is 130 mg/L as CaCO3 (7.6 gpg), with a range of 35.6 to 150 mg/L. Treatment-plant samples alone read much softer, so confidence in the exact figure is moderate. The water is hard on median.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 7.6 gpg |
|---|---|
| Utility | Cal-Water Service Co.-Oroville |
How Oroville compares
- Tap water in Oroville is 16 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 826 of 1372 in the United States (1 = hardest); 39 % of these cities have softer water.
- In California it is number 217 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Colfax, 69 km away (0.6 gpg).
- Nearest city with clearly harder water: Live Oak, 26 km away (10.6 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 Oroville
| 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 Oroville water hard or soft?
It is hard: 130 mg/L as CaCO₃ (7.6 gpg, 7.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Oroville 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 Oroville water?
7.6 gpg, equal to 7.3 °dH, 13 °fH or 130 mg/L calcium carbonate.
What dishwasher salt setting should I use in Oroville?
For 130 mg/L (7.3 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Oroville?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: California SWRCB Division of Drinking Water, EDT lab results, system CA0410005 (2025-04). Method: own measurement. California SWRCB Division of Drinking Water, EDT lab results, system CA0410005 · Outdated figure? Tell us