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LakeQuality

Lake Gem

B
Grade B — Good
Good · #245 of 320 lakes in the county · 2 ft clear · Eutrophic · from D
Eutrophic

Lake Gem in Orange County, Florida has a water quality grade of B (Good). Water clarity: 2 ft visibility. Phosphorus: 36 µg/L.

Clarity
2 ft
Typical in August
87°F
Type
Eutrophic
Trend
Declining

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Lake Gem is a productive, nutrient-rich eutrophic 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, Lake Gem ranks #245 for water quality.

Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-09-23. Grade methodology: LakeQuality methodology.

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Swimming Safety

Grade only

Bacteria 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.

A
Bacteria swim-safety grade: A
from E. coli testing · 44 samples, 4 seasons

Based on E. coli testing, Lake Gem never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 44 samples across 4 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.

Get alerts for Lake Gem

Water Quality Grade: B (Good)

Very murky, less than 2 ft of visibility. Phosphorus level: 36 µg/L. Trophic State Index: 61.

MetricValueGrade
Water Clarity (Secchi Depth)2 ftNot graded
Phosphorus36 µg/LGood
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)61Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Lake Gem

Compare lakeside cabins, hotels, and vacation rentals near Lake Gem 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 Gem

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

Lake Gem typically sits around 87°F at the surface in August. Summer average is about 87°F. Usually warmest in Jul (about 87°F) and coldest in Jan (about 63°F). These are typical values by month — not a live reading.

Jan
63°
Feb
68°
Mar
71°
Apr
77°
May
81°
Jun
86°
Jul
87°
Aug
87°
Sep
85°
Oct
78°
Nov
75°
Dec
68°

Typical surface water temperature by month, from 49 field readings (20122025) via the EPA Water Quality Portal. See the full Lake Gem water temperature breakdown →

Fishing Lake Gem

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.191 m/yr6
Phosphorus Declining+2.94 µg/L/yr6
See year-by-year chart →

EPA Impairment Status

Lake Gem is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).

Causes of impairment

Algal growthImpaired biota (cause unknown)Nutrients (phosphorus, nitrogen)

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit FL2997V · Official waterbody report · Matched by proximity (0.01 km)

County Ranking

Ranked #245 of 320 lakes in Orange County

Nearby Lakes in Orange County

Frequently asked questions about Lake Gem

Where is Lake Gem?

Lake Gem 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 Gem?

Lake Gem in Orange County, Florida has a water quality grade of B (Good). Water clarity: 2 ft visibility. Phosphorus: 36 µg/L.

Is Lake Gem safe to swim in?

Based on E. coli testing, Lake Gem never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 44 samples across 4 seasons. That works out to a bacteria swim-safety grade of A — a historical summary of past testing, not a current reading. Lake Gem 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 Gem?

Lake Gem typically sits around 87°F at the surface in August, from 49 EPA Water Quality Portal field readings (2012–2025). That is a typical value for the month, not a live reading.

Planning a trip around Canaveral?

Lake Gem is about 39 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

Where this data comes from

88 measurements from 1 monitoring station, 2022–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Submitting organization not recorded for these samples88 samples · 2022–2025
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