Thein Lake
Thein Lake in Stearns County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 10.5 ft visibility.
- Clarity
- 10.5 ft
- Typical in August
- 77°F
- Max depth
- ~25 ft est.
- Public access
- No
Next lake in Stearns County
Why Thein Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Thein Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Thein Lake is a lake in Stearns County, Minnesota with an estimated average depth of about 25 feet. Limited fish-species data available. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-15. Grade methodology: LakeGrade methodology.
Watch Thein Lake water quality
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Thein Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Good clarity, visible to about 10.5 ft. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Thein Lake
Compare lakeside cabins, hotels, and vacation rentals near Thein Lake in Stearns 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.
Top-rated places to stay near Thein Lake
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Water Temperature
Thein Lake typically sits around 77°F at the surface in August. Summer average is about 66°F. Usually warmest in Aug (about 77°F) and coldest in Jun (about 53°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 14 field readings (2010–2025) via the EPA Water Quality Portal. See the full Thein Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~25 ft est. |
| Average Depth | ~8 ft est. |
| Public Access | No |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Minnesota has not published bathymetry for Thein 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 Thein Lake
EPA Impairment Status
Thein Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN73-0133-04 · Official waterbody report · Matched by proximity (1.37 km)
Graded lakes near Thein Lake
Thein Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Stearns County
Frequently asked questions about Thein Lake
What is the water quality grade for Thein Lake?
- Thein Lake in Stearns County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 10.5 ft visibility.
Is Thein Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Thein Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
What is the water temperature of Thein Lake?
- Thein Lake typically sits around 77°F at the surface in August, from 14 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Thein Lake?
- No published bathymetric survey covers Thein Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 25 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
5 measurements from 1 monitoring station, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA5 samples · 2025
Analytical methods
- Field measurement/observation, generic 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