Deep Lake
Deep Lake in Seminole County, Florida has a water quality grade of C (Fair). Water clarity: 6.9 ft visibility. Phosphorus: 44 µg/L.
- Clarity
- 6.9 ft
- Typical in September
- 87°F
- Type
- Eutrophic
- Trend
- ↓ Declining
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Deep Lake is a productive, nutrient-rich eutrophic lake in Seminole County, Florida. Water quality is graded C based on 1 sampling years through 2025. Overall water quality is declining over recent sampling years. Compared to the 121 other monitored lakes in Seminole County, Deep Lake ranks #99 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-06-02. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLimited data
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Moderate clarity, visible to about 6.9 ft. Phosphorus level: 44 µg/L. Trophic State Index: 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.9 ft | Not graded |
| Phosphorus | 44 µg/L | Fair |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Deep Lake
Compare lakeside cabins, hotels, and vacation rentals near Deep Lake in Seminole 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 Deep Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Florida’s top lakes →
Water Temperature
Deep Lake typically sits around 87°F at the surface in September. Summer average is about 86°F. Usually warmest in Sep (about 87°F) and coldest in Dec (about 71°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 37 field readings (2015–2025) via the EPA Water Quality Portal. See the full Deep Lake water temperature breakdown →
Fishing Deep Lake
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.08 m/yr | 6 |
| Phosphorus | ↓ Declining | +1.04 µg/L/yr | 6 |
EPA Impairment Status
Deep Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4C).
Causes of impairment
Source: EPA ATTAINS assessment unit FL3009J · Official waterbody report · Matched by proximity (1.66 km)
County Ranking
Ranked #99 of 122 lakes in Seminole County
Nearby Lakes With Higher Grades
Deep Lake holds Grade C. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Seminole County
Frequently asked questions about Deep Lake
Where is Deep Lake?
- Deep Lake is a lake in Seminole County, Florida. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Deep Lake?
- Deep Lake in Seminole County, Florida has a water quality grade of C (Fair). Water clarity: 6.9 ft visibility. Phosphorus: 44 µg/L.
Is Deep Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Deep Lake has a water quality grade of C (Fair). Always check local health department advisories before swimming.
What is the water temperature of Deep Lake?
- Deep Lake typically sits around 87°F at the surface in September, from 37 EPA Water Quality Portal field readings (2015–2025). That is a typical value for the month, not a live reading.
Explore Deep Lake across LakeQuality
Planning a trip around Canaveral?
Deep Lake is about 32 miles from Canaveral National Seashore. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Canaveral →More Florida Lake Rankings
Other Grade C Lakes in Florida
Eutrophic Lakes in Florida
Where this data comes from
50 measurements from 3 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples36 samples · 2020–2025
- Submitting organization not recorded for these samples14 samples · 2022–2024
Monitoring station identifiers (3)
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