Lake Oroville
Lake Oroville in Butte County, California has a water quality grade of A (Excellent). Phosphorus: 6 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Surface area: 15800 acres.
- Area
- 15,800 acres
- Type
- Oligotrophic
Lake Oroville is a 15,800-acre cold, clear oligotrophic lake in Butte County, California. Water quality is graded A based on 2 sampling years through 2023.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2023-08-18. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
No clarity data. Phosphorus level: 6 µg/L. Chlorophyll-a: 1.8 µg/L. Trophic State Index: 33.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 6 µg/L | Good |
| Chlorophyll-a (Algae) | 1.8 µg/L | Good |
| Trophic State Index (TSI) | 33 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Lake Oroville
Compare lakeside cabins, hotels, and vacation rentals near Lake Oroville in Butte County, California — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Lake Oroville
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 15,800 acres |
No bathymetric survey has been published for Lake Oroville, so its depth is not documented here.
Fishing Lake Oroville
Reservoir Info (USACE NID)
Lake Oroville is a man-made reservoir impounded by the Oroville (completed 1968), built primarily for flood risk reduction on the Feather River; earth-type dam, 770 ft tall and 6,920 ft long.
- Surface area
- 15,800 ac
- Normal storage
- 3,540,000 ac-ft
- Max storage
- 3,540,000 ac-ft
- Drainage area
- 3,611 sq mi
- Hazard class
- High
- Owner
- California Department of Water Resources
All listed purposes: Flood Risk Reduction;Irrigation;Recreation;Hydroelectric;Water Supply.
Source: USACE National Inventory of Dams, NID ID CA00035 · Operator website
County Ranking
Ranked #1 of 1 lakes in Butte County
Nearby Lakes in Butte County
Frequently asked questions about Lake Oroville
Where is Lake Oroville?
- Lake Oroville is a lake in Butte County, California. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lake Oroville?
- Lake Oroville in Butte County, California has a water quality grade of A (Excellent). Phosphorus: 6 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Surface area: 15800 acres.
Is Lake Oroville safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Lake Oroville has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 1.8 µg/L. Always check local health department advisories before swimming.
Explore Lake Oroville across LakeGrade
More California Lake Rankings
Other Grade A Lakes in California
Oligotrophic Lakes in California
Where this data comes from
6 measurements from 3 monitoring stations, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- USGS California Water Science Center
USGS-CA6 samples · 2023
Analytical methods
- Nutrients, wu, persulfate, color
- Pigments, algae, EPA445.0 w/ACTN
Monitoring station identifiers (3)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.