Apex Reservoir
Wake County, North CarolinaView mapDirections
Nutrients and algae run well above the regional average.
↓ down from D at the last regrade
- Hypereutrophic
- #8 of 14 in the county
- 41 ft max depth
Apex Reservoir in Wake County, North Carolina has a water quality grade of F (Algae-prone). Water clarity: 1.8 ft visibility. Phosphorus: 50 µg/L. Chlorophyll-a (algae): 35.5 µg/L.
- Clarity
- 1.8 ft
- Max depth
- ~41 ft est.
- Type
- Hypereutrophic
- Trend
- ↓ Declining
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Stays near Apex Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Apex Reservoir 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 Apex Reservoir are listed below.
Top-rated places to stay near Apex Reservoir
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Watch Apex Reservoir’s letter
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Apex Reservoir is a highly nutrient-loaded hypereutrophic lake in Wake County, North Carolina with an estimated average depth of about 41 feet. Water quality is graded F based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. Compared to the 13 other monitored lakes in Wake County, Apex Reservoir ranks #8 for water quality.
Source: EPA Water Quality Portal sampling records, NCDEQ, last sampled 2025-09-11. 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. Apex Reservoir is listed impaired under Clean Water Act §303(d) (IR 4A) for impaired biota (cause unknown). Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 1.8 ft of visibility. Phosphorus 50 µg/L. Chlorophyll-a 35.5 µg/L. TSI 65. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.8 ft | Not graded |
| Phosphorus | 50 µg/L | Poor |
| Chlorophyll-a (Algae) | 35.5 µg/L | Poor |
| Trophic State Index (TSI) | 65 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~41 ft est. |
| Average Depth | ~9 ft est. |
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 Apex Reservoir.
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 Apex Reservoir
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↓ Declining | +1 µg/L/yr | 2 |
| Chlorophyll-a | ↓ Declining | +3.9 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Apex Reservoir is a man-made reservoir impounded by the Apex Lake Dam (completed 1968), built primarily for recreation on the Williams Creek; earth-type dam, 22 ft tall and 735 ft long.
- Normal storage
- 136 ac-ft
- Max storage
- 163 ac-ft
- Drainage area
- 2.24 sq mi
- Hazard class
- High
- Owner
- Town of Apex
All listed purposes: Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID NC00933 · Operator website
EPA Impairment Status
Apex Reservoir is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NC27-43-2 · Official waterbody report · Matched by proximity (0.37 km)
County Ranking
Ranked #8 of 14 lakes in Wake County
Nearby Lakes With Higher Grades
Apex Reservoir 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 Apex Reservoir
Where is Apex Reservoir?
- Apex Reservoir 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 Apex Reservoir?
- Apex Reservoir in Wake County, North Carolina has a water quality grade of F (Algae-prone). Water clarity: 1.8 ft visibility. Phosphorus: 50 µg/L. Chlorophyll-a (algae): 35.5 µg/L.
Is Apex Reservoir safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Apex Reservoir is listed impaired under Clean Water Act §303(d) (IR 4A) for impaired biota (cause unknown). Check local advisories before you swim.
How deep is Apex Reservoir?
- No published bathymetric survey covers Apex Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 41 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Apex Reservoir 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
38 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
21NC03WQ38 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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)