Mcdonald Lake
Mcdonald Lake in Washington County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 5 ft visibility. Phosphorus: 83 µg/L. Chlorophyll-a (algae): 26 µg/L. Maximum depth: 28 ft. Surface area: 45.45 acres.
- Clarity
- 5 ft
- Typical in August
- 76°F
- Max depth
- 28 ft
- Area
- 45 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- No
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Mcdonald Lake →
Next lake in Washington County
Mcdonald Lake is a 45-acre productive, nutrient-rich eutrophic lake in Washington County, Minnesota with a maximum depth of 28 feet. Water quality is graded D based on 2 sampling years through 2024. 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 74 other monitored lakes in Washington County, Mcdonald Lake ranks #52 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-07. 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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Murky, only visible to about 5 ft. Phosphorus level: 83 µg/L. Chlorophyll-a: 26 µg/L. Trophic State Index: 61.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5 ft | Not graded |
| Phosphorus | 83 µg/L | Poor |
| Chlorophyll-a (Algae) | 26 µg/L | Poor |
| Trophic State Index (TSI) | 61 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Mcdonald Lake
Compare lakeside cabins, hotels, and vacation rentals near Mcdonald Lake in Washington 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 Mcdonald Lake are listed below.
Top-rated places to stay near Mcdonald Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Mcdonald Lake typically sits around 76°F at the surface in August. Summer average is about 72°F. Usually warmest in Aug (about 76°F) and coldest in May (about 53°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 57 field readings (2011–2024) via the EPA Water Quality Portal. See the full Mcdonald Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 28 ft |
| Surface Area | 45 acres |
| Shoreline Length | 1.3 mi |
| Littoral Zone | 66% |
| Public Access | No |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fishing Mcdonald Lake
DNR Fisheries Survey Summary
1 survey on file from MN DNR Fisheries. Most recent: 1991-07-02 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 55.00 | 0.7 lb |
| Bluegill | 29.70 | 0.26 lb |
| Walleye | 13.00 | 2.27 lb |
| Northern Pike | 1.10 | 8.82 lb |
| Largemouth Bass | 1.00 | 1.5 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
From the 1991-07-02 survey
CATCH RATES FOR WAE, BLG, LMB, AND BLB WERE ABOVE LOCAL AND STATE-WIDE VALUES. CATCH RATES FOR NOP WERE BELOW LOCAL AND STATE-WIDE MEDIAN VALUES.
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Mcdonald Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — CloverdaleFisheries Lake Survey · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.077 m/yr | 4 |
| Phosphorus | ↓ Declining | +14 µg/L/yr | 2 |
EPA Impairment Status
Mcdonald Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN82-0010-00 · Official waterbody report
County Ranking
Ranked #52 of 75 lakes in Washington County
Nearby Lakes in Washington County
Frequently asked questions about Mcdonald Lake
What is the water quality grade for Mcdonald Lake?
- Mcdonald Lake in Washington County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 5 ft visibility. Phosphorus: 83 µg/L. Chlorophyll-a (algae): 26 µg/L. Maximum depth: 28 ft. Surface area: 45.45 acres.
Is Mcdonald Lake safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Mcdonald Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 26 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Mcdonald Lake?
- Mcdonald Lake typically sits around 76°F at the surface in August, from 57 EPA Water Quality Portal field readings (2011–2024). That is a typical value for the month, not a live reading.
How deep is Mcdonald Lake?
- Mcdonald Lake has a maximum depth of 28 feet. The lake covers 45.45 acres.
Explore Mcdonald Lake across LakeGrade
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Where this data comes from
62 measurements from 2 monitoring stations, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA62 samples · 2020–2024
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Analysis of Chlorophyll in Periphyton and Plankton
- 2120 B ~ Color in Water by Visual Comparison
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