Mary Jess Lake
Mary Jess Lake in Orange County, Florida has a water quality grade of B (Good). Water clarity: 6.4 ft visibility. Phosphorus: 10.5 µg/L.
- Clarity
- 6.4 ft
- Typical in August
- 87°F
- Type
- Mesotrophic
- Trend
- ↓ Declining
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Mary Jess Lake is a mesotrophic lake in Orange County, Florida. Water quality is graded B based on 1 sampling years through 2025. Overall water quality is declining over recent sampling years. Compared to the 319 other monitored lakes in Orange County, Mary Jess Lake ranks #183 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-03-18. Grade methodology: LakeQuality methodology.
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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, Mary Jess Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 31 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)
Murky, only visible to about 6.4 ft. Phosphorus level: 10.5 µg/L. Trophic State Index: 44.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.4 ft | Not graded |
| Phosphorus | 10.5 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 44 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Mary Jess Lake
Compare lakeside cabins, hotels, and vacation rentals near Mary Jess Lake 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 Mary Jess Lake
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Water Temperature
Mary Jess Lake typically sits around 87°F at the surface in August. Summer average is about 87°F. Usually warmest in Jul (about 88°F) and coldest in Feb (about 61°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 50 field readings (2010–2025) via the EPA Water Quality Portal. See the full Mary Jess Lake water temperature breakdown →
Fishing Mary Jess Lake
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.8 m/yr | 5 |
| Phosphorus | ↓ Declining | +0.3 µg/L/yr | 5 |
EPA Impairment Status
Mary Jess Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit FL3168W7 · Official waterbody report · Matched by proximity (1.98 km)
County Ranking
Ranked #183 of 320 lakes in Orange County
Nearby Lakes in Orange County
Frequently asked questions about Mary Jess Lake
Where is Mary Jess Lake?
- Mary Jess Lake 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 Mary Jess Lake?
- Mary Jess Lake in Orange County, Florida has a water quality grade of B (Good). Water clarity: 6.4 ft visibility. Phosphorus: 10.5 µg/L.
Is Mary Jess Lake safe to swim in?
- Based on E. coli testing, Mary Jess Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 31 samples across 8 seasons. That works out to a bacteria swim-safety grade of A — a historical summary of past testing, not a current reading. Mary Jess 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.
What is the water temperature of Mary Jess Lake?
- Mary Jess Lake typically sits around 87°F at the surface in August, from 50 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
Explore Mary Jess Lake across LakeQuality
More Florida Lake Rankings
Other Grade B Lakes in Florida
Mesotrophic Lakes in Florida
Where this data comes from
61 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 samples61 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