Curfman Lake
Curfman Lake in Becker County, Minnesota has a water quality grade of A (Excellent). Water clarity: 12 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 5.2 µg/L. Maximum depth: 24 ft. Surface area: 120.91 acres.
- Clarity
- 12 ft
- Typical in August
- 73°F
- Max depth
- 24 ft
- Area
- 121 acres
- Type
- Mesotrophic
- Trend
- ↓ Declining
- Public access
- No
Next lake in Becker County
Curfman Lake is a 121-acre mesotrophic lake in Becker County, Minnesota with a maximum depth of 24 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted. Compared to the 83 other monitored lakes in Becker County, Curfman Lake ranks #57 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-17. 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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Good clarity, visible to about 12 ft. Phosphorus level: 20 µg/L. Chlorophyll-a: 5.2 µg/L. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12 ft | Not graded |
| Phosphorus | 20 µg/L | Good |
| Chlorophyll-a (Algae) | 5.2 µg/L | Good |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Curfman Lake
Compare lakeside cabins, hotels, and vacation rentals near Curfman Lake in Becker 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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Water Temperature
Curfman Lake typically sits around 73°F at the surface in August. Summer average is about 70°F. Usually warmest in Aug (about 73°F) and coldest in May (about 58°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 205 field readings (2010–2025) via the EPA Water Quality Portal. See the full Curfman Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 24 ft |
| Surface Area | 121 acres |
| Shoreline Length | 1.9 mi |
| Littoral Zone | 70% |
| Public Access | No |
Fishing Curfman Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.163 m/yr | 6 |
| Phosphorus | → Stable | +0.23 µg/L/yr | 6 |
| Chlorophyll-a | → Stable | 0 µg/L/yr | 6 |
EPA Impairment Status
Curfman 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 MN03-0360-00 · Official waterbody report · Matched by proximity (1.67 km)
County Ranking
Ranked #57 of 84 lakes in Becker County
Nearby Lakes in Becker County
Frequently asked questions about Curfman Lake
What is the water quality grade for Curfman Lake?
- Curfman Lake in Becker County, Minnesota has a water quality grade of A (Excellent). Water clarity: 12 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 5.2 µg/L. Maximum depth: 24 ft. Surface area: 120.91 acres.
Is Curfman Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Curfman Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 5.2 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Curfman Lake?
- Curfman Lake typically sits around 73°F at the surface in August, from 205 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Curfman Lake?
- Curfman Lake has a maximum depth of 24 feet. The lake covers 120.91 acres.
Explore Curfman Lake across LakeGrade
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Where this data comes from
24 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
MNPCA24 samples · 2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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