C

Marion-Lou Lake

Marion County, FloridaEutrophic

Marion-Lou Lake is a productive, nutrient-rich eutrophic lake in Marion County, Florida. Water quality is graded C based on 2 sampling years through 2025. Compared to the 41 other monitored lakes in Marion County, Marion-Lou Lake ranks #25 for water quality.

Source: EPA Water Quality Portal sampling records, Florida DNR, last sampled 2025-03-27. Grade methodology: LakeGrade methodology.

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Swimming Safety

Generally safe for swimming, moderate water quality

Water Quality Grade: C, Fair

Very murky, less than 3.3 ft of visibility. Phosphorus level: 18.5 µg/L. Trophic State Index: 53.

Metric	Value	Grade
Water Clarity (Secchi Depth)	3.3 ft	D
Phosphorus	18.5 µg/L	B
Chlorophyll-a (Algae)	No data
Trophic State Index (TSI)	53	Eutrophic

High nutrients, frequent algae, reduced clarity

Location

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County Ranking

Ranked #25 of 42 lakes in Marion County

Cleaner Lakes Within 30 Miles

Marion-Lou Lake holds Grade C. 2 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Marion County

Marion-Eaton Lake

Lake Eaton Center

Lkeatonctr Lake

Marion-Charles Lake

Marion-Mill Dam Lake

Marion-Halfmoon Lake

More Florida Lake Rankings

Cleanest lakes in Florida

Top 25 by overall water quality score

Best swimming lakes in Florida

Grade A/B + low algae filter

Family fishing lakes in Florida

Panfish-rich, public access

All Florida lakes

Full state directory

Other Grade C Lakes in Florida

Lake Lancaster West

Orange County · Clarity: 3.5 ft

Eastern Lake Outlet

Walton County · Clarity: 4.2 ft

Seminole-Secret Lake

Seminole County · Clarity: 4.5 ft

Seminole County · Clarity: 2.9 ft

Polk-Fannie Lake

Polk County · Clarity: 3.5 ft

Volusia-North Talmadge Lake

Volusia County · Clarity: 4.5 ft

Eutrophic Lakes in Florida

Lake Lancaster West Flagler-Emerald Lake Eastern Lake Outlet Seminole-Secret Lake

Lake Size & Watershed

Watershed (drainage) area

67 sq mi

Surface area

94 acres

Mean depth (est.)

9.5 ft

Shoreline

1.4 mi

Elevation

46 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.

Data Sources

Water quality data from the EPA Water Quality Portal

Lake size & watershed from HydroLAKES (HydroSHEDS)

Grading methodology based on Metropolitan Council standards

Most recent sample: 2025-03-27

Monitoring stations: 3

Where to stay near Marion-Lou Lake

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