Lake Johio
Lake Johio in Orange County, Florida has a water quality grade of B (Good). Water clarity: 10 ft visibility. Phosphorus: 6 µg/L.
- Clarity
- 10 ft
- Typical in August
- 83°F
- Type
- Oligotrophic
- Trend
- ↑ Improving
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Lake Johio is a cold, clear oligotrophic lake in Orange County, Florida. Water quality is graded B based on 1 sampling years through 2025. Overall water quality is improving over recent sampling years. Compared to the 319 other monitored lakes in Orange County, Lake Johio ranks #19 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-02-05. 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 Johio rarely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 3.7% of 27 samples across 8 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)
Good clarity, visible to about 10 ft. Phosphorus level: 6 µg/L. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | Not graded |
| Phosphorus | 6 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Lake Johio
Compare lakeside cabins, hotels, and vacation rentals near Lake Johio in Orange 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 Johio
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Planning a whole trip? See where to stay at Florida’s top lakes →
Water Temperature
Lake Johio typically sits around 83°F at the surface in August. Summer average is about 83°F. Usually warmest in Aug (about 83°F) and coldest in Feb (about 66°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 26 field readings (2018–2025) via the EPA Water Quality Portal. See the full Lake Johio water temperature breakdown →
Fishing Lake Johio
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.24 m/yr | 5 |
| Phosphorus | ↑ Improving | -0.4 µg/L/yr | 5 |
EPA Impairment Status
Lake Johio is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit FL3002D · Official waterbody report · Matched by proximity (2.53 km)
County Ranking
Ranked #19 of 320 lakes in Orange County
Nearby Lakes in Orange County
Frequently asked questions about Lake Johio
Where is Lake Johio?
- Lake Johio is a lake in Orange 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 Johio?
- Lake Johio in Orange County, Florida has a water quality grade of B (Good). Water clarity: 10 ft visibility. Phosphorus: 6 µg/L.
Is Lake Johio safe to swim in?
- Based on E. coli testing, Lake Johio rarely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 3.7% of 27 samples across 8 seasons. That works out to a bacteria swim-safety grade of B — a historical summary of past testing, not a current reading. Lake Johio 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 Johio?
- Lake Johio typically sits around 83°F at the surface in August, from 26 EPA Water Quality Portal field readings (2018–2025). That is a typical value for the month, not a live reading.
Explore Lake Johio across LakeQuality
More Florida Lake Rankings
Other Grade B Lakes in Florida
Oligotrophic Lakes in Florida
Where this data comes from
42 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples42 samples · 2020–2025
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