Monroe-Northside Lake
Monroe County, FloridaEutrophic
Monroe-Northside Lake is a productive, nutrient-rich eutrophic lake in Monroe County, Florida. Water quality is graded C based on 2 sampling years through 2024. Compared to the 1 other monitored lakes in Monroe County, Monroe-Northside Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Florida DNR, last sampled 2024-12-06. Grade methodology: LakeGrade methodology.
Watch Monroe-Northside Lake water quality
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 3.9 ft. Phosphorus level: 23.5 µg/L. Trophic State Index: 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.9 ft | D |
| Phosphorus | 23.5 µg/L | B |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Location
County Ranking
Ranked #1 of 2 lakes in Monroe County
Nearby Lakes in Monroe County
More Florida Lake Rankings
Other Grade C Lakes in Florida
Orange County · Clarity: 3.5 ft
Walton County · Clarity: 4.2 ft
Seminole County · Clarity: 4.5 ft
Seminole County · Clarity: 2.9 ft
Polk County · Clarity: 3.5 ft
Volusia County · Clarity: 4.5 ft
Eutrophic Lakes in Florida
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Monroe-Northside Lake under Clean Water Act (NPDES) discharge permits.
- Adolfos Custom Boat WorkUnknown · 1.5 mi away · NPDES FLY970099
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Data Sources
Water quality data from the EPA Water Quality Portal
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-12-06
Monitoring stations: 2
Where to stay near Monroe-Northside Lake
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