Polk-Marianna Lake
Polk-Marianna Lake in Polk County, Florida has a water quality grade of B (Good). Water clarity: 2 ft visibility. Phosphorus: 26.5 µg/L.
- Clarity
- 2 ft
- Type
- Eutrophic
- Trend
- ↓ Declining
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Polk-Marianna Lake is a productive, nutrient-rich eutrophic lake in Polk County, Florida. Water quality is graded B based on 1 sampling years through 2022. Overall water quality is declining over recent sampling years. Compared to the 176 other monitored lakes in Polk County, Polk-Marianna Lake ranks #26 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2022-04-01. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLow algae
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.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Very murky, less than 2 ft of visibility. Phosphorus level: 26.5 µg/L. Trophic State Index: 59.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2 ft | Not graded |
| Phosphorus | 26.5 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 59 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Polk-Marianna Lake
Compare lakeside cabins, hotels, and vacation rentals near Polk-Marianna Lake in Polk 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.
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Fishing Polk-Marianna Lake
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.276 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.91 µg/L/yr | 6 |
EPA Impairment Status
Polk-Marianna Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit FL1521L · Official waterbody report · Matched by proximity (0.15 km)
County Ranking
Ranked #26 of 177 lakes in Polk County
Nearby Lakes in Polk County
Frequently asked questions about Polk-Marianna Lake
Where is Polk-Marianna Lake?
- Polk-Marianna Lake is a lake in Polk County, Florida. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Polk-Marianna Lake?
- Polk-Marianna Lake in Polk County, Florida has a water quality grade of B (Good). Water clarity: 2 ft visibility. Phosphorus: 26.5 µg/L.
Is Polk-Marianna Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Polk-Marianna Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
Explore Polk-Marianna Lake across LakeQuality
More Florida Lake Rankings
Other Grade B Lakes in Florida
Eutrophic Lakes in Florida
Where this data comes from
123 measurements from 3 monitoring stations, 2020–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- FLORIDA LAKEWATCH
21FLKWAT_WQX123 samples · 2020–2022
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