Hardwood Lake
Hardwood Lake in Carlton County, Minnesota has a water quality grade of C (Fair). Water clarity: 5.1 ft visibility. Phosphorus: 200 µg/L. Chlorophyll-a (algae): 5.1 µg/L.
- Clarity
- 5.1 ft
- Mean depth
- ~12 ft est.
- Type
- Eutrophic
- Trend
- ↓ Declining
Next lake in Carlton County
Hardwood Lake is a productive, nutrient-rich eutrophic lake in Carlton County, Minnesota with an estimated average depth of about 12 feet. Water quality is graded C based on 2 sampling years through 2024. Overall water quality is declining over recent sampling years. Compared to the 21 other monitored lakes in Carlton County, Hardwood Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-07-15. Grade methodology: LakeGrade methodology.
Watch Hardwood 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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Murky, only visible to about 5.1 ft. Phosphorus level: 200 µg/L. Chlorophyll-a: 5.1 µg/L. Trophic State Index: 60.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.1 ft | Not graded |
| Phosphorus | 200 µg/L | Poor |
| Chlorophyll-a (Algae) | 5.1 µg/L | Good |
| Trophic State Index (TSI) | 60 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Hardwood Lake
Compare lakeside cabins, hotels, and vacation rentals near Hardwood 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.
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Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~12 ft est. |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for Hardwood 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 Hardwood Lake
Water Quality Trend: ↓ Declining
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +1.283 m/yr | 2 |
| Phosphorus | ↓ Declining | +64.29 µg/L/yr | 3 |
| Chlorophyll-a | ↓ Declining | +0.66 µg/L/yr | 3 |
County Ranking
Ranked #9 of 22 lakes in Carlton County
Nearby Lakes With Higher Grades
Hardwood Lake holds Grade C. 2 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 Hardwood Lake
What is the water quality grade for Hardwood Lake?
- Hardwood Lake in Carlton County, Minnesota has a water quality grade of C (Fair). Water clarity: 5.1 ft visibility. Phosphorus: 200 µg/L. Chlorophyll-a (algae): 5.1 µg/L.
Is Hardwood Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Hardwood Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 5.1 µg/L. Always check local health department advisories before swimming.
How deep is Hardwood Lake?
- No published bathymetric survey covers Hardwood Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 12 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Hardwood Lake across LakeGrade
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Where this data comes from
38 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_WQX38 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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder