Monroe-Northside Lake
Monroe County, FloridaView mapDirections
Florida DEP publishes the water-quality measurements for Monroe-Northside Lake. Here is what has been measured.
- Eutrophic
- Public access
Monroe-Northside Lake in Monroe County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 23.5 µg/L.
Monroe-Northside Lake is a productive, nutrient-rich eutrophic lake in Monroe County, Florida. Water clarity is declining over recent sampling years. Limited fish-species data available. Public access is available. 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, FDEP, last sampled 2024-12-06. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Monroe-Northside Lake is safe to swim in today is a call for the Florida Department of Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Monroe-Northside Lake
These are the measurements Florida DEP publishes for Monroe-Northside Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 3.9 ft. Phosphorus 23.5 µg/L. TSI 54.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 23.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 54 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
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Fishing Monroe-Northside Lake
Water Quality Trend: Stable
Based on 4 years of monitoring (2020–2024).
Water clarity
Worsening2 years
Phosphorus
Improving-6.15 µg/L/yr4 years
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.
Nearby Lakes in Monroe County
Frequently asked questions about Monroe-Northside Lake
Where is Monroe-Northside Lake?
- Monroe-Northside Lake is a lake in Monroe County, Florida. Its water-quality measurements are published by Florida DEP and shown on this page as reported.
What is the water quality of Monroe-Northside Lake?
- Monroe-Northside Lake in Monroe County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 23.5 µg/L.
Is Monroe-Northside Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Can I fish at Monroe-Northside Lake?
- Public access to Monroe-Northside Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Florida's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
52 measurements from 2 monitoring stations, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- FLORIDA LAKEWATCH
21FLKWAT_WQX52 samples · 2020–2024
Monitoring station identifiers (2)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Regulated discharger data from EPA ECHO (ICIS-NPDES)