Lake-Joanna
Lake County, FloridaMesotrophic
Lake-Joanna is a mesotrophic lake in Lake County, Florida. Water quality is graded B based on 2 sampling years through 2025. Compared to the 316 other monitored lakes in Lake County, Lake-Joanna ranks #15 for water quality.
Source: EPA Water Quality Portal sampling records, Florida DNR, last sampled 2025-03-19. Grade methodology: LakeGrade methodology.
Watch Lake-Joanna water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Moderate clarity, visible to about 7.5 ft. Phosphorus level: 9 µg/L. Trophic State Index: 42.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.5 ft | C |
| Phosphorus | 9 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 42 | Mesotrophic |
Moderate nutrients, good water quality
Location
County Ranking
Ranked #15 of 317 lakes in Lake County
Cleaner Lakes Within 30 Miles
Lake-Joanna holds Grade B. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Lake County
More Florida Lake Rankings
Other Grade B Lakes in Florida
Bay County · Clarity: 4 ft
Brevard County · Clarity: 9.8 ft
Alachua County · Clarity: 5.5 ft
Seminole County · Clarity: 5 ft
Marion County · Clarity: 7 ft
Hillsborough County · Clarity: 6 ft
Mesotrophic Lakes in Florida
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Data Sources
Water quality data from the EPA Water Quality Portal
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-03-19
Monitoring stations: 3
Where to stay near Lake-Joanna
Compare lakeside cabins, hotels, and vacation rentals near Lake-Joanna in Lake County, Florida — live availability and prices for your trip.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.