Mud Lake
Mud Lake in Hennepin County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 0.9 ft visibility. Phosphorus: 150 µg/L. Chlorophyll-a (algae): 123.5 µg/L.
- Clarity
- 0.9 ft
- Typical in August
- 78°F
- Mean depth
- ~11 ft est.
- Type
- Hypereutrophic
- Trend
- ↑ Improving
- Public access
- No
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Mud Lake →
Next lake in Hennepin County
Mud Lake is a highly nutrient-loaded hypereutrophic lake in Hennepin County, Minnesota with an estimated average depth of about 11 feet. Water quality is graded F based on 2 sampling years through 2021. Overall water quality is improving over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted. Compared to the 80 other monitored lakes in Hennepin County, Mud Lake ranks #56 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2021-09-13. 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)
Very murky, less than 0.9 ft of visibility. Phosphorus level: 150 µg/L. Chlorophyll-a: 123.5 µg/L. Trophic State Index: 78.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.9 ft | Not graded |
| Phosphorus | 150 µg/L | Poor |
| Chlorophyll-a (Algae) | 123.5 µg/L | Poor |
| Trophic State Index (TSI) | 78 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Mud Lake
Compare lakeside cabins, hotels, and vacation rentals near Mud Lake in Hennepin 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 Mud Lake are listed below.
Top-rated places to stay near Mud Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Mud Lake typically sits around 78°F at the surface in August. Summer average is about 77°F. Usually warmest in Jul (about 79°F) and coldest in Oct (about 45°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 47 field readings (2016–2021) via the EPA Water Quality Portal.
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~11 ft est. |
| Public Access | No |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for Mud Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Fishing Mud 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: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.075 m/yr | 6 |
| Phosphorus | → Stable | -0.47 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -9.19 µg/L/yr | 6 |
EPA Impairment Status
Mud 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 MN10-0042-00 · Official waterbody report · Matched by proximity (1.47 km)
County Ranking
Ranked #56 of 81 lakes in Hennepin County
Nearby Lakes With Higher Grades
Mud Lake holds Grade F. 3 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 Hennepin County
Frequently asked questions about Mud Lake
What is the water quality grade for Mud Lake?
- Mud Lake in Hennepin County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 0.9 ft visibility. Phosphorus: 150 µg/L. Chlorophyll-a (algae): 123.5 µg/L.
Is Mud 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. Mud Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 123.5 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Mud Lake?
- Mud Lake typically sits around 78°F at the surface in August, from 47 EPA Water Quality Portal field readings (2016–2021). That is a typical value for the month, not a live reading.
How deep is Mud Lake?
- No published bathymetric survey covers Mud Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 11 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
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Where this data comes from
58 measurements from 1 monitoring station, 2020–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA58 samples · 2020–2021
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