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LakeQuality

Mud Lake

NR
Not yet rated
1.6 ft clear · Eutrophic
Limited DataEutrophic

Mud Lake in Otter Tail County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 1.6 ft visibility.

Clarity
1.6 ft
Mean depth
~10 ft est.
Public access
Yes

Next lake in Otter Tail County

CLittle Pine Lake9.5 ft clear · Otter Tail CountyView →
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Why Mud 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 Mud Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). 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.

Mud Lake is a lake in Otter Tail County, Minnesota with an estimated average depth of about 10 feet. Limited fish-species data available. Public access is available with 1 public boat landing.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2021-06-07. Grade methodology: LakeGrade methodology.

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Swimming Safety

Not rated

Limited data

Not rated for swimming — there is not enough monitoring data to judge this lake

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Water quality measurements for Mud Lake

These readings exist but do not meet the evidence bar for an A–F grade — see why.

Very murky, less than 1.6 ft of visibility. Trophic State Index: 70.

MetricValueGrade
Water Clarity (Secchi Depth)1.6 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)70Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Mud Lake

Compare lakeside cabins, hotels, and vacation rentals near Mud 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 Mud Lake

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Lake Details

CharacteristicValue
Average Depth~10 ft est.
Public AccessYes

Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for Mud Lake.

Lake Size & Watershed

Watershed (drainage) area
3 sq mi
Surface area
346 acres
Mean depth (modeled estimate)
~10 ft est.
Shoreline
3.3 mi
Elevation
1,322 ft

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.

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Little Pine Lake (Southwest)Public

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.

zebra mussel

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

Mercury

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN56-0142-00 · Official waterbody report · Matched by proximity (1.66 km)

Regulated Pollution Sources Nearby

2 EPA-permitted facilities operate within about 5 miles of Mud Lake under Clean Water Act (NPDES) discharge permits. 2 facilities have a reported Clean Water Act violation in the past three years.

  • Bongards' Creameries - Perham
    Perham · 2.3 mi away · NPDES MN0047228
    Recent violation
  • Perham Resource Recovery Facility
    Perham · 2.5 mi away · NPDES MN0067415
    Recent violation

Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.

Graded lakes near Mud Lake

Mud Lake has no grade, but these lakes within a short drive do.

Nearby Lakes in Otter Tail County

Frequently asked questions about Mud Lake

What is the water quality grade for Mud Lake?

Mud Lake in Otter Tail County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 1.6 ft visibility.

Is Mud Lake safe to swim in?

Not rated for swimming — there is not enough monitoring data to judge this lake. Mud Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.

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 10 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.

Are there boat ramps on Mud Lake?

Mud Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Little Pine Lake (Southwest). Public access is listed as yes.

Where this data comes from

2 measurements from 1 monitoring station, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA2 samples · 2021

Analytical methods

  • Field measurement/observation, generic method
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

Regulated discharger data from EPA ECHO (ICIS-NPDES)

Lake size & watershed from HydroLAKES (HydroSHEDS)

Lake details from Minnesota DNR LakeFinder

Named boat-access points from the USGS National Boat Ramps inventory