Washington Lake
Washington Lake in Le Sueur County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 4.5 ft visibility. Phosphorus: 122 µg/L. Chlorophyll-a (algae): 51.3 µg/L. Maximum depth: 51 ft. Surface area: 1516.11 acres.
- Clarity
- 4.5 ft
- Typical in August
- 72°F
- Max depth
- 51 ft
- Area
- 1,516 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 4
- Open water
- 240 days
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Washington Lake →
Next lake in Le Sueur County
Free interactive depth-contour map of Washington Lake, reaching a maximum surveyed depth of 40 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Washington Lake is a 1,516-acre productive, nutrient-rich eutrophic lake in Le Sueur County, Minnesota with a maximum depth of 51 feet. Water quality is graded F based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 18 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 2 public boat landings. Compared to the 12 other monitored lakes in Le Sueur County, Washington Lake ranks #8 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyAlgae risk
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.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
Murky, only visible to about 4.5 ft. Phosphorus level: 122 µg/L. Chlorophyll-a: 51.3 µg/L. Trophic State Index: 66.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.5 ft | Not graded |
| Phosphorus | 122 µg/L | Poor |
| Chlorophyll-a (Algae) | 51.3 µg/L | Poor |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Washington Lake
Compare lakeside cabins, hotels, and vacation rentals near Washington Lake in Le Sueur 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 Washington Lake are listed below.
Top-rated places to stay near Washington Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Washington 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 54°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 522 field readings (2011–2025) via the EPA Water Quality Portal. See the full Washington Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 51 ft |
| Surface Area | 1,516 acres |
| Shoreline Length | 12.1 mi |
| Littoral Zone | 52% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Washington Lake (West)Public
- Washington Lake (North)Public
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Washington Lake
DNR Fisheries Survey Summary
17 surveys on file from MN DNR Fisheries. Most recent: 2023-10-10 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Freshwater Drum | 30.60 | 1.19 lb |
| Bluegill | 14.20 | 0.25 lb |
| Yellow Bass | 13.14 | 1.24 lb |
| Yellow Perch | 10.11 | 0.18 lb |
| Black Crappie | 9.28 | 0.31 lb |
| White Crappie | 7.41 | 0.33 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.
Freshwater Drum
Bluegill
Yellow Bass
Yellow Perch
From the 2023-10-10 survey
A survey targeting age-0 Walleyes was conducted at Lake Washington on 10 October 2023 using 59 minutes of standard boat electrofishing. Twenty-five age-0 Walleyes were sampled for a catch rate of 25.4/hour on-time. Age-0 Walleye averaged 8.8 inches and ranged from 6.7 inches to 11.4 inches. The Lake Washington…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Washington Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — WashingtonFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — WashingtonFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — WashingtonPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.028 m/yr | 6 |
| Phosphorus | ↓ Declining | +14.75 µg/L/yr | 3 |
| Chlorophyll-a | → Stable | -0.6 µg/L/yr | 3 |
Ice Season
Historical ice data from Minnesota DNR (132 observations).
Estimated open water season: 240 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-01 (2024) | 2018-04-30 (2018) |
| Ice-In | 1991-11-01 (1991) | 2017-12-24 (2017) |
Most recent ice-out: 2025-03-15
EPA Impairment Status
Washington Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN40-0117-00 · Official waterbody report
County Ranking
Ranked #8 of 13 lakes in Le Sueur County
Nearby Lakes With Higher Grades
Washington Lake holds Grade F. 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 Le Sueur County
Frequently asked questions about Washington Lake
What is the water quality grade for Washington Lake?
- Washington Lake in Le Sueur County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 4.5 ft visibility. Phosphorus: 122 µg/L. Chlorophyll-a (algae): 51.3 µg/L. Maximum depth: 51 ft. Surface area: 1516.11 acres.
Is Washington Lake safe to swim in?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Washington Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 51.3 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Washington Lake?
- Washington Lake typically sits around 72°F at the surface in August, from 522 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Washington Lake?
- Washington Lake has a maximum depth of 51 feet. The lake covers 1516.11 acres.
What fish are in Washington Lake?
- Fish species found in Washington Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, freshwater drum, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white crappie, white sucker, yellow bullhead, yellow perch. Washington Lake is located in Le Sueur County, Minnesota.
When does Washington Lake thaw?
- Washington Lake typically has ice-out around Apr 4. Ice typically forms around Nov 30. The open water season is approximately 240 days.
Are there boat ramps on Washington Lake?
- Washington Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Washington Lake (West), Washington Lake (North). Public access is listed as yes.
Explore Washington Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Le Sueur County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Minnesota River Watershed, ranked by water quality
High nutrients, frequent algae, reduced clarity
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Washington Lake
Other Grade F Lakes in Minnesota
Eutrophic Lakes in Minnesota
Compare Washington Lake With Nearby Lakes
Where this data comes from
899 measurements from 6 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
MNPCA899 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity, Nephelometric Method
Monitoring station identifiers (6)
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
Ice data from Minnesota DNR Climate