Sewell Lake
Sewell Lake in Otter Tail County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 5 ft visibility. Maximum depth: 52 ft. Surface area: 368.8 acres.
- Clarity
- 5 ft
- Typical in August
- 72°F
- Max depth
- 52 ft
- Area
- 369 acres
- Trend
- → Stable
- Public access
- Yes
Next lake in Otter Tail County
Why Sewell 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 Sewell 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.
Sewell Lake is a 369-acre lake in Otter Tail County, Minnesota with a maximum depth of 52 feet. The lake supports 13 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 2 public boat landings.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-08-22. Grade methodology: LakeGrade methodology.
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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 Sewell Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 5 ft. Trophic State Index: 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Sewell Lake
Compare lakeside cabins, hotels, and vacation rentals near Sewell Lake in Otter Tail 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 Sewell Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Sewell Lake typically sits around 72°F at the surface in August. Summer average is about 69°F. Usually warmest in Aug (about 72°F) and coldest in May (about 59°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 39 field readings (2010–2025) via the EPA Water Quality Portal. See the full Sewell Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Sewell Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (139,316 cells/mL) on July 4, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 52 ft |
| Surface Area | 369 acres |
| Shoreline Length | 5.6 mi |
| Littoral Zone | 46% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Sewell LakePublic
- Jolly Ann LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Sewell Lake
DNR Fisheries Survey Summary
10 surveys on file from MN DNR Fisheries. Most recent: 2024-06-24 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Largemouth Bass | 39.95 | 1.74 lb |
| Bluegill | 38.59 | 0.16 lb |
| Spottail Shiner | 17.55 | — |
| Fathead Minnow | 16.99 | — |
| Yellow Perch | 13.79 | 0.1 lb |
| IOD | 11.40 | — |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Largemouth Bass
Bluegill
Yellow Perch
From the 2024-06-24 survey
A targeted survey of nearshore fish species in Sewell Lake was conducted on June 24th-25th, 2024, by Index of Biological Integrity (IBI) Program. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where possible. Backpack…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Sewell Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — SewellFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Sewell (1054)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — SewellFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — SewellPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.026 m/yr | 5 |
EPA Impairment Status
Sewell 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 MN56-0408-00 · Official waterbody report
Graded lakes near Sewell Lake
Sewell Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Otter Tail County
Frequently asked questions about Sewell Lake
What is the water quality grade for Sewell Lake?
- Sewell Lake in Otter Tail County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 5 ft visibility. Maximum depth: 52 ft. Surface area: 368.8 acres.
Is Sewell Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Sewell 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 Sewell Lake?
- Sewell Lake typically sits around 72°F at the surface in August, from 39 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Sewell Lake?
- Sewell Lake has a maximum depth of 52 feet. The lake covers 368.8 acres.
What fish are in Sewell Lake?
- Fish species found in Sewell Lake include black bullhead, black crappie, bluegill, brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, yellow bullhead, yellow perch. Sewell Lake is located in Otter Tail County, Minnesota.
Does Sewell Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Sewell Lake (clouds, ice, or an off-season gap). The most recent reading was high (139,316 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Sewell Lake?
- Sewell Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Sewell Lake, Jolly Ann Lake. Public access is listed as yes.
Explore Sewell Lake across LakeGrade
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Where this data comes from
48 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA47 samples · 2020–2025 - Minnesota Department of Agriculture - Pesticide Monitoring
MNDA_PESTICIDE1 sample · 2022
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (2)
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
Named boat-access points from the USGS National Boat Ramps inventory