Gertnwdk Lake
Gertnwdk Lake in Lake County, Florida has a water quality grade of B (Good). Water clarity: 3.3 ft visibility. Phosphorus: 40 µg/L.
- Clarity
- 3.3 ft
- Max depth
- ~37 ft est.
- Type
- Eutrophic
- Trend
- ↓ Declining
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Gertnwdk Lake is a productive, nutrient-rich eutrophic lake in Lake County, Florida with an estimated average depth of about 37 feet. Water quality is graded B based on 1 sampling years through 2024. Overall water quality is declining over recent sampling years. Compared to the 127 other monitored lakes in Lake County, Gertnwdk Lake ranks #69 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2024-10-28. Grade methodology: LakeQuality methodology.
Watch Gertnwdk Lake water quality
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Swimming Safety
Grade onlyBacteria A
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.
Based on E. coli testing, Gertnwdk Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 8 samples across 2 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Florida’s current beach and health-department advisories before swimming.
Water Quality Grade: B (Good)
Very murky, less than 3.3 ft of visibility. Phosphorus level: 40 µg/L. Trophic State Index: 59.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.3 ft | Not graded |
| Phosphorus | 40 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 59 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Gertnwdk Lake
Compare lakeside cabins, hotels, and vacation rentals near Gertnwdk Lake in Lake County, Florida — 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 Gertnwdk Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~37 ft est. |
| Average Depth | ~16 ft est. |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Florida has not published bathymetry for Gertnwdk 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 Gertnwdk Lake
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -2.875 m/yr | 5 |
| Phosphorus | ↓ Declining | +2.5 µg/L/yr | 5 |
County Ranking
Ranked #69 of 128 lakes in Lake County
Nearby Lakes in Lake County
Frequently asked questions about Gertnwdk Lake
Where is Gertnwdk Lake?
- Gertnwdk Lake is a lake in Lake County, Florida. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Gertnwdk Lake?
- Gertnwdk Lake in Lake County, Florida has a water quality grade of B (Good). Water clarity: 3.3 ft visibility. Phosphorus: 40 µg/L.
Is Gertnwdk Lake safe to swim in?
- Based on E. coli testing, Gertnwdk Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 8 samples across 2 seasons. That works out to a bacteria swim-safety grade of A — a historical summary of past testing, not a current reading. Gertnwdk Lake has a water quality grade of B (Good). Bacteria levels can spike quickly after heavy rain, so always check Florida's current beach and health-department advisories before you swim.
How deep is Gertnwdk Lake?
- No published bathymetric survey covers Gertnwdk Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 37 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Gertnwdk Lake across LakeQuality
More Florida Lake Rankings
Other Grade B Lakes in Florida
Eutrophic Lakes in Florida
Where this data comes from
19 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples19 samples · 2020–2024
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)