Wildhorse Reservoir
Elko County, Nevada3,035 acresView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- Impaired · Mercury
- #9 of 9 in the county
Wildhorse Reservoir in Elko County, Nevada has a water quality grade of F (Algae-prone). Water clarity: 5.9 ft visibility. Phosphorus: 107 µg/L. Chlorophyll-a (algae): 67.2 µg/L. Surface area: 3035 acres.
- Clarity
- 5.9 ft
- Area
- 3,035 acres
- Type
- Hypereutrophic
- Phosphorus
- 107 µg/L
- Chlorophyll-a
- 67.2 µg/L
- Trend
- ↑ Improving
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Stays near Wildhorse Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Wildhorse Reservoir in Elko County, Nevada — 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Wildhorse Reservoir are listed below.
Top-rated places to stay near Wildhorse Reservoir
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Watch Wildhorse Reservoir’s letter
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Wildhorse Reservoir is a 3,035-acre highly nutrient-loaded hypereutrophic lake in Elko County, Nevada. Water quality is graded F based on 2 sampling years through 2022. Overall water quality is improving over recent sampling years. Compared to the 8 other monitored lakes in Elko County, Wildhorse Reservoir ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, NDEP, last sampled 2022-09-28. Grade methodology: LakeQuality methodology.
What Wildhorse Reservoir is good for
From access and monitoring records, not editorial picks.
- Big water3,035 acres
Swimming Safety
Grade onlyAlgae risk
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.
The F is nutrients and algae, not a swimming clearance. Wildhorse Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury), nutrients (phosphorus, nitrogen), oxygen depletion (low DO). Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Murky, only visible to about 5.9 ft. Phosphorus 107 µg/L. Chlorophyll-a 67.2 µg/L. TSI 65. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.9 ft | Not graded |
| Phosphorus | 107 µg/L | Poor |
| Chlorophyll-a (Algae) | 67.2 µg/L | Poor |
| Trophic State Index (TSI) | 65 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
→ Wildhorse Reservoir water level: the live USGS gauge reading
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 3,035 acres |
No bathymetric survey has been published for Wildhorse Reservoir, so its depth is not documented here.
Fishing Wildhorse Reservoir
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↑ Improving | -49 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Wildhorse Reservoir is a man-made reservoir impounded by the Wild Horse (completed 1969), built primarily for irrigation on the East Fork Owyhee RIver; concrete-type dam, 110 ft tall and 435 ft long.
- Surface area
- 3,035 ac
- Normal storage
- 71,660 ac-ft
- Max storage
- 92,500 ac-ft
- Drainage area
- 204 sq mi
- Hazard class
- High
- Owner
- BIA
All listed purposes: Irrigation;Recreation.
Source: USACE National Inventory of Dams, NID ID NV10119 · Operator website
EPA Impairment Status
Wildhorse Reservoir is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit NV03-OW-25-B_00 · Official waterbody report
County Ranking
Ranked #9 of 9 lakes in Elko County
Nearby Lakes With Higher Grades
Wildhorse Reservoir holds Grade F. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Elko County
Frequently asked questions about Wildhorse Reservoir
Where is Wildhorse Reservoir?
- Wildhorse Reservoir is a lake in Elko County, Nevada. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Wildhorse Reservoir?
- Wildhorse Reservoir in Elko County, Nevada has a water quality grade of F (Algae-prone). Water clarity: 5.9 ft visibility. Phosphorus: 107 µg/L. Chlorophyll-a (algae): 67.2 µg/L. Surface area: 3035 acres.
Is Wildhorse Reservoir safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Wildhorse Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury), nutrients (phosphorus, nitrogen), oxygen depletion (low DO). Check local advisories before you swim.
Explore Wildhorse Reservoir across LakeQuality
4 thermal springs within 21.9 mi, nearest Wild Horse Hot Springs
Species activity outlook by water temperature and season
Where to stay at Nevada's top lakes, each with its grade
Very high nutrients, dense algae, poor clarity
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Where this data comes from
23 measurements from 2 monitoring stations, 2018–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Bureau of Reclamation
1119USBR_WQX23 samples · 2018–2022
Analytical methods
- Depth, Secchi disk depth
- Phosphorus by Single Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity by Nephelometry
Monitoring station identifiers (2)
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.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database