Spruce Lake
Spruce Lake in Carlton County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 2.3 ft visibility. Phosphorus: 110 µg/L. Chlorophyll-a (algae): 9.1 µg/L.
- Clarity
- 2.3 ft
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- No
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Spruce Lake →
Next lake in Carlton County
Spruce Lake is a productive, nutrient-rich eutrophic lake in Carlton County, Minnesota. Water quality is graded D based on 2 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 21 other monitored lakes in Carlton County, Spruce Lake ranks #19 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-07-08. Grade methodology: LakeGrade methodology.
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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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 2.3 ft of visibility. Phosphorus level: 110 µg/L. Chlorophyll-a: 9.1 µg/L. Trophic State Index: 63.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.3 ft | Not graded |
| Phosphorus | 110 µg/L | Poor |
| Chlorophyll-a (Algae) | 9.1 µg/L | Fair |
| Trophic State Index (TSI) | 63 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Spruce Lake
Compare lakeside cabins, hotels, and vacation rentals near Spruce Lake in Carlton 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Spruce Lake are listed below.
Top-rated places to stay near Spruce Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Fishing Spruce Lake
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.453 m/yr | 5 |
| Phosphorus | ↓ Declining | +72.6 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -0.46 µg/L/yr | 5 |
EPA Impairment Status
Spruce 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_121 · Official waterbody report · Matched by proximity (0 km)
County Ranking
Ranked #19 of 22 lakes in Carlton County
Nearby Lakes With Higher Grades
Spruce Lake holds Grade D. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Carlton County
Frequently asked questions about Spruce Lake
What is the water quality grade for Spruce Lake?
- Spruce Lake in Carlton County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 2.3 ft visibility. Phosphorus: 110 µg/L. Chlorophyll-a (algae): 9.1 µg/L.
Is Spruce Lake safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Spruce Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 9.1 µg/L. Always check local health department advisories before swimming.
Explore Spruce Lake across LakeGrade
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Species activity outlook by water temperature and season
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High nutrients, frequent algae, reduced clarity
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Where this data comes from
55 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_WQX55 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