Turtle Lake Inlet
Turtle Lake Inlet in Cook County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar.
- Typical in August
- 75°F
- Trend
- → Stable
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Why Turtle Lake Inlet has no grade
We grade a lake only when the monitoring record supports a letter: 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 Turtle Lake Inlet, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
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.
Turtle Lake Inlet is a lake in Cook County, Minnesota. Water clarity is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-07-22. Grade methodology: LakeQuality methodology.
Watch Turtle Lake Inlet 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 Turtle Lake Inlet
These readings exist but are not enough for an A–F grade — see why.
No clarity data.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples |
Where to stay near Turtle Lake Inlet
Compare lakeside cabins, hotels, and vacation rentals near Turtle Lake Inlet in Cook 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 Turtle Lake Inlet
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Water Temperature
Turtle Lake Inlet typically sits around 75°F at the surface in August. Summer average is about 72°F. Usually warmest in Aug (about 75°F) and coldest in May (about 51°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 69 field readings (2011–2025) via the EPA Water Quality Portal. See the full Turtle Lake Inlet water temperature breakdown →
Fishing Turtle Lake Inlet
Water Quality Trend: → Stable
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -10.222 m/yr | 4 |
| Phosphorus | ↑ Improving | -2.49 µg/L/yr | 4 |
| Chlorophyll-a | → Stable | -0.03 µg/L/yr | 4 |
Graded lakes near Turtle Lake Inlet
Turtle Lake Inlet has no grade, but these lakes within a short drive do.
Nearby Lakes in Cook County
Frequently asked questions about Turtle Lake Inlet
Where is Turtle Lake Inlet?
- Turtle Lake Inlet is a lake in Cook County, Minnesota. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Turtle Lake Inlet?
- Turtle Lake Inlet in Cook County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar.
Is Turtle Lake Inlet safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Turtle Lake Inlet 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 Turtle Lake Inlet?
- Turtle Lake Inlet typically sits around 75°F at the surface in August, from 69 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
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Where this data comes from
4 measurements from 1 monitoring station, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Grand Portage Reservation
GPC5_WQX4 samples · 2021–2025
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.