Twin Lake
St. Louis County, MinnesotaView mapDirections
Minnesota PCA publishes the water-quality measurements for Twin Lake. Here is what has been measured.
- Limited data
Twin Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.6 ft visibility. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 2.5 µg/L.
Twin Lake is a lake in St. Louis County, Minnesota.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-09-15. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Twin Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Twin Lake
These are the measurements Minnesota PCA publishes for Twin 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 3.6 ft. Phosphorus 13 µg/L. Chlorophyll-a 2.5 µg/L. TSI 46.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 13µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 2.5µg/L | Measured, not scored 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. | 46 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Fishing Twin Lake
Nearby Lakes in St. Louis County
Frequently asked questions about Twin Lake
Where is Twin Lake?
- Twin Lake is a lake in St. Louis County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Twin Lake?
- Twin Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.6 ft visibility. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 2.5 µg/L.
Is Twin Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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Where this data comes from
5 measurements from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA5 samples · 2022
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2130 B ~ Nephelometric Method
- 2120 B ~ Color in Water by Visual Comparison
Monitoring station identifiers (1)
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.