Fairfax Lake
Osage County, Oklahoma111 acresView mapDirections
Oklahoma DEQ publishes the water-quality measurements for Fairfax Lake. Here is what has been measured.
- 25 ft max depth
- Limited data
Fairfax Lake in Osage County, Oklahoma has water-quality measurements published by Oklahoma DEQ, shown here as reported. Water clarity: 2.6 ft visibility. Surface area: 111 acres.
Fairfax Lake is a 111-acre lake in Osage County, Oklahoma with an estimated average depth of about 25 feet. Overall water quality is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, ODEQ, last sampled 2024-07-29. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Fairfax Lake is safe to swim in today is a call for the Oklahoma Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Fairfax Lake
These are the measurements Oklahoma DEQ publishes for Fairfax Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2.6 ft of visibility. TSI 64.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 64 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Fairfax Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~25 ft est.
Surface area
111 acres
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Oklahoma has not published bathymetry for Fairfax Lake.
Lake Size & Watershed
Watershed (drainage) area
260 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.3 mi
HydroLAKES / HydroSHEDS
Elevation
886 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
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Stays near Fairfax Lake
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Fishing Fairfax Lake
Water Quality Trend: Worsening
Based on 4 years of monitoring (2016–2024).
Water clarity
Worsening4 years
Reservoir Info (USACE NID)
Fairfax Lake is a man-made reservoir impounded by the Fairfax (completed 1936), built primarily for water supply on the Wild Creek; earth-type dam, 55 ft tall and 1,300 ft long.
- Surface area
- 111 ac
- Normal storage
- 1,795 ac-ft
- Max storage
- 2,492 ac-ft
- Drainage area
- 8.81 sq mi
- Hazard class
- High
- Owner
- City of Fairfax
Source: USACE National Inventory of Dams, NID ID OK11020 · Operator website
Nearby Lakes in Osage County
Frequently asked questions about Fairfax Lake
Where is Fairfax Lake?
- Fairfax Lake is a lake in Osage County, Oklahoma. Its water-quality measurements are published by Oklahoma DEQ and shown on this page as reported.
What is the water quality of Fairfax Lake?
- Fairfax Lake in Osage County, Oklahoma has water-quality measurements published by Oklahoma DEQ, shown here as reported. Water clarity: 2.6 ft visibility. Surface area: 111 acres.
Is Fairfax Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Fairfax Lake?
- No published bathymetric survey covers Fairfax Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 25 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 111 acres.
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Where this data comes from
37 measurements from 3 monitoring stations, 2016–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- OWRB Lakes Monitoring
OKWRB-LAKES_WQX37 samples · 2016–2024
Analytical methods
- OWRB Lakes Field Data Collection
- Determination of Turbidity
Monitoring station identifiers (3)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)