Lake Iamonia
Lake Iamonia in Leon County, Florida has a water quality grade of B (Good). Water clarity: 2 ft visibility. Phosphorus: 42 µg/L.
- Clarity
- 2 ft
- Typical in August
- 83°F
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Lake Iamonia is a productive, nutrient-rich eutrophic lake in Leon County, Florida. Water quality is graded B based on 1 sampling years through 2024. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 58 other monitored lakes in Leon County, Lake Iamonia ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2024-10-30. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyBacteria B
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, Lake Iamonia rarely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 3.7% of 27 samples across 7 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 2 ft of visibility. Phosphorus level: 42 µg/L. Trophic State Index: 63.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2 ft | Not graded |
| Phosphorus | 42 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 63 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Lake Iamonia
Compare lakeside cabins, hotels, and vacation rentals near Lake Iamonia in Leon 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 Lake Iamonia
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Water Temperature
Lake Iamonia typically sits around 83°F at the surface in August. Summer average is about 84°F. Usually warmest in Jul (about 85°F) and coldest in Feb (about 58°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 49 field readings (2010–2024) via the EPA Water Quality Portal. See the full Lake Iamonia water temperature breakdown →
Recreation & Access
- Bull Headley LandingPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Lake Iamonia
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.195 m/yr | 5 |
| Phosphorus | ↑ Improving | -18.25 µg/L/yr | 5 |
EPA Impairment Status
Lake Iamonia 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 FL442 · Official waterbody report
County Ranking
Ranked #2 of 59 lakes in Leon County
Nearby Lakes in Leon County
Frequently asked questions about Lake Iamonia
Where is Lake Iamonia?
- Lake Iamonia is a lake in Leon County, Florida. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lake Iamonia?
- Lake Iamonia in Leon County, Florida has a water quality grade of B (Good). Water clarity: 2 ft visibility. Phosphorus: 42 µg/L.
Is Lake Iamonia safe to swim in?
- Based on E. coli testing, Lake Iamonia rarely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 3.7% of 27 samples across 7 seasons. That works out to a bacteria swim-safety grade of B — a historical summary of past testing, not a current reading. Lake Iamonia 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.
What is the water temperature of Lake Iamonia?
- Lake Iamonia typically sits around 83°F at the surface in August, from 49 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
Are there boat ramps on Lake Iamonia?
- Lake Iamonia has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Bull Headley Landing. Public access is listed as yes.
Explore Lake Iamonia across LakeQuality
More Florida Lake Rankings
Other Grade B Lakes in Florida
Eutrophic Lakes in Florida
Where this data comes from
37 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 samples37 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
Impairment status from EPA ATTAINS 303(d) database
Named boat-access points from the USGS National Boat Ramps inventory