Big Lake
Wake County, North Carolina25 acresView mapDirections
Nutrients and algae run well above the regional average.
↓ down from D at the last regrade
- Hypereutrophic
- #9 of 14 in the county
- 24 ft max depth
Big Lake in Wake County, North Carolina has a water quality grade of F (Algae-prone). Water clarity: 2.3 ft visibility. Phosphorus: 50 µg/L. Chlorophyll-a (algae): 37 µg/L. Surface area: 25 acres.
- Clarity
- 2.3 ft
- Max depth
- ~24 ft est.
- Area
- 25 acres
- Type
- Hypereutrophic
- Trend
- ↑ Improving
Stays via Stay22
Stays near Big Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Lake in Wake County, North Carolina — 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 Big Lake are listed below.
Top-rated places to stay near Big Lake
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Watch Big Lake’s letter
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Big Lake is a 25-acre highly nutrient-loaded hypereutrophic lake in Wake County, North Carolina with an estimated average depth of about 24 feet. Water quality is graded F based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. Compared to the 13 other monitored lakes in Wake County, Big Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, NCDEQ, last sampled 2025-09-04. Grade methodology: LakeQuality methodology.
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. Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 2.3 ft of visibility. Phosphorus 50 µg/L. Chlorophyll-a 37 µg/L. TSI 64. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.3 ft | Not graded |
| Phosphorus | 50 µg/L | Poor |
| Chlorophyll-a (Algae) | 37 µg/L | Poor |
| Trophic State Index (TSI) | 64 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~24 ft est. |
| Average Depth | ~14 ft est. |
| Surface Area | 25 acres |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. North Carolina has not published bathymetry for Big Lake.
Lake Size & Watershed
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.
Fishing Big Lake
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↑ Improving | -2 µg/L/yr | 2 |
| Chlorophyll-a | → Stable | -0.5 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Big Lake is a man-made reservoir impounded by the Umstead Park Lake Dam #1 (completed 1940), built primarily for recreation on the Sycamore Creek; earth-type dam, 30 ft tall and 410 ft long.
- Surface area
- 25 ac
- Normal storage
- 360 ac-ft
- Max storage
- 432 ac-ft
- Drainage area
- 7.11 sq mi
- Hazard class
- Low
- Owner
- NC Department of Natural and Cultural Resources
Source: USACE National Inventory of Dams, NID ID NC00881 · Operator website
County Ranking
Ranked #9 of 14 lakes in Wake County
Nearby Lakes With Higher Grades
Big Lake holds Grade F. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Wake County
Frequently asked questions about Big Lake
Where is Big Lake?
- Big Lake is a lake in Wake County, North Carolina. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Big Lake?
- Big Lake in Wake County, North Carolina has a water quality grade of F (Algae-prone). Water clarity: 2.3 ft visibility. Phosphorus: 50 µg/L. Chlorophyll-a (algae): 37 µg/L. Surface area: 25 acres.
Is Big Lake safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
How deep is Big Lake?
- No published bathymetric survey covers Big Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 24 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 25 acres.
Explore Big Lake across LakeQuality
Species activity outlook by water temperature and season
Where to stay at North Carolina's top lakes, each with its grade
Very high nutrients, dense algae, poor clarity
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Where this data comes from
35 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Carolina Dept of Environmental Quality NCDEQ-DWR WQX
21NC03WQ35 samples · 2020–2025
Analytical methods
- WSSSOP
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 2130 B ~ Nephelometric Method
Monitoring station identifiers (1)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)