Sarah Lake
Sarah Lake in Polk County, Minnesota has a water quality grade of B (Good). Water clarity: 7.7 ft visibility. Phosphorus: 29.5 µg/L. Chlorophyll-a (algae): 9.5 µg/L. Maximum depth: 27 ft. Surface area: 365.93 acres.
- Clarity
- 7.7 ft
- Max depth
- 27 ft
- Area
- 366 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 16
- Open water
- 222 days
Next lake in Polk County
Sarah Lake is a 366-acre productive, nutrient-rich eutrophic lake in Polk County, Minnesota with a maximum depth of 27 feet (13-foot average). Water quality is graded B based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 10 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 18 other monitored lakes in Polk County, Sarah Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-24. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
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.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Moderate clarity, visible to about 7.7 ft. Phosphorus level: 29.5 µg/L. Chlorophyll-a: 9.5 µg/L. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.7 ft | Not graded |
| Phosphorus | 29.5 µg/L | Good |
| Chlorophyll-a (Algae) | 9.5 µg/L | Good |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Sarah Lake
Compare lakeside cabins, hotels, and vacation rentals near Sarah Lake in Polk 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 |
|---|---|
| Maximum Depth | 27 ft |
| Average Depth | 12.7 ft |
| Surface Area | 366 acres |
| Shoreline Length | 5.3 mi |
| Littoral Zone | 49% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Sarah LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Sarah Lake
DNR Fisheries Survey Summary
13 surveys on file from MN DNR Fisheries. Most recent: 2021-07-19 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Spottail Shiner | 25.08 | — |
| Yellow Perch | 20.51 | 0.18 lb |
| Bluegill | 13.01 | 0.31 lb |
| Walleye | 8.89 | 2.14 lb |
| White Sucker | 6.99 | 2.3 lb |
| Largemouth Bass | 5.60 | 1.02 lb |
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.
Yellow Perch
Bluegill
Walleye
White Sucker
From the 2021-07-19 survey
Lake Sarah is a 366-acre lake located in Polk County four miles south of Erskine. This productive lake possesses a heavily developed shoreline and occasionally experiences large water level fluctuations. Lake Sarah provides angling opportunities for Walleye, Northern Pike, Bluegill, and Black Crappie. A standard…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Sarah Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — SarahFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Sarah (1955)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — SarahFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — SarahPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.104 m/yr | 6 |
| Phosphorus | ↑ Improving | -2.46 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +1.31 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (29 observations).
Estimated open water season: 222 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-03-21 (2012) | 1996-05-06 (1996) |
| Ice-In | 1993-11-06 (1993) | 1999-12-10 (1999) |
Most recent ice-out: 2012-03-21
County Ranking
Ranked #7 of 19 lakes in Polk County
Nearby Lakes With Higher Grades
Sarah Lake holds Grade B. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Polk County
Frequently asked questions about Sarah Lake
What is the water quality grade for Sarah Lake?
- Sarah Lake in Polk County, Minnesota has a water quality grade of B (Good). Water clarity: 7.7 ft visibility. Phosphorus: 29.5 µg/L. Chlorophyll-a (algae): 9.5 µg/L. Maximum depth: 27 ft. Surface area: 365.93 acres.
Is Sarah Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Sarah Lake has a water quality grade of B (Good). Algae concentration (chlorophyll-a) is 9.5 µg/L. Always check local health department advisories before swimming.
How deep is Sarah Lake?
- Sarah Lake has a maximum depth of 27 feet and an average depth of 12.7 feet. The lake covers 365.93 acres.
What fish are in Sarah Lake?
- Fish species found in Sarah Lake include black bullhead, black crappie, bluegill, brown bullhead, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow perch. Sarah Lake is located in Polk County, Minnesota.
When does Sarah Lake thaw?
- Sarah Lake typically has ice-out around Apr 16. Ice typically forms around Nov 24. The open water season is approximately 222 days.
Are there boat ramps on Sarah Lake?
- Sarah Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Sarah Lake. Public access is listed as yes.
Explore Sarah Lake across LakeGrade
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Where this data comes from
85 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA85 samples · 2020–2025
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate