East Twin Lake
East Twin Lake in St. Louis County, Minnesota has a water quality grade of A (Excellent). Water clarity: 2.8 ft visibility. Phosphorus: 117 µg/L. Chlorophyll-a (algae): 6.9 µg/L.
- Clarity
- 2.8 ft
- Mean depth
- ~10 ft est.
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- No
Next lake in St. Louis County
East Twin Lake is a productive, nutrient-rich eutrophic lake in St. Louis County, Minnesota with an estimated average depth of about 10 feet. Water quality is graded A based on 1 sampling years through 2024. Overall water quality is improving over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted. Compared to the 67 other monitored lakes in St. Louis County, East Twin Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-07-30. Grade methodology: LakeGrade methodology.
Watch East Twin Lake water quality
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Swimming Safety
Grade onlyLimited data
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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Very murky, less than 2.8 ft of visibility. Phosphorus level: 117 µg/L. Chlorophyll-a: 6.9 µg/L. Trophic State Index: 62.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.8 ft | Not graded |
| Phosphorus | 117 µg/L | Not graded |
| Chlorophyll-a (Algae) | 6.9 µg/L | Good |
| Trophic State Index (TSI) | 62 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near East Twin Lake
Compare lakeside cabins, hotels, and vacation rentals near East Twin Lake in St. Louis County, Minnesota — 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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Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~10 ft est. |
| Public Access | No |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for East Twin Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Fishing East Twin Lake
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for East Twin Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Aquatic Plant Report — East Twin (0543)Aquatic Plant Report · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.854 m/yr | 5 |
| Phosphorus | ↓ Declining | +73.05 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -1.07 µg/L/yr | 5 |
EPA Impairment Status
East Twin Lake is officially listed as impaired under Clean Water Act §303(d) in the 2019 EPA reporting cycle.
Causes of impairment
Source: EPA ATTAINS assessment unit FDL_105 · Official waterbody report
County Ranking
Ranked #7 of 68 lakes in St. Louis County
Nearby Lakes in St. Louis County
Frequently asked questions about East Twin Lake
What is the water quality grade for East Twin Lake?
- East Twin Lake in St. Louis County, Minnesota has a water quality grade of A (Excellent). Water clarity: 2.8 ft visibility. Phosphorus: 117 µg/L. Chlorophyll-a (algae): 6.9 µg/L.
Is East Twin Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. East Twin Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 6.9 µg/L. Always check local health department advisories before swimming.
How deep is East Twin Lake?
- No published bathymetric survey covers East Twin Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 10 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
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Where this data comes from
25 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Fond du Lac Band of Chippewa (MN)
FONDULAC_WQX25 samples · 2020–2024
Analytical methods
- Phosphorus by Two Reagent Colorimetry
- Phosphorus by Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
- 10200 H ~ Chlorophyll a-b-c Determination
- Color, APHA Platinum-Cobalt
- For determination of Copper by the Bicinchoninate method.
Monitoring station identifiers (1)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder