Mud Lake
Polk County, Wisconsin96 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Mud Lake. Here is what has been measured.
- Eutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- Curly-Leaf Pondweed
- 7 ft max depth
- Public access
- Limited data
Mud Lake in Polk County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2 ft visibility. Phosphorus: 93 µg/L. Maximum depth: 7 ft. Surface area: 96 acres.
Wisconsin DNR lists Musky as present on Mud Lake. DNR survey details →
Mud Lake is a 96-acre productive, nutrient-rich eutrophic lake in Polk County, Wisconsin with a maximum depth of 7 feet. Overall water quality is improving over recent sampling years. The lake supports 4 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available. Compared to the 54 other monitored lakes in Polk County, Mud Lake ranks #43 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2020-09-14. Methodology: how these readings are compared.
What Mud Lake is good for
From access and monitoring records, not editorial picks.
- Fishing4 species recorded
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Mud Lake is listed impaired under Clean Water Act §303(d) (IR 5R) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Mud Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Mud Lake
These are the measurements Wisconsin DNR publishes for Mud Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2 ft of visibility. Phosphorus 93 µg/L. TSI 68.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 93µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 68 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Mud Lake
Answers come straight from the public measurements and survey records on this page.
Wisconsin DNR lists Musky as present on Mud Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Mud Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 2 stations on file (most recent sample 2020).
Fish Species (DNR-rated)
Lake Details
Max depth
7 ft
Surface area
96 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
1 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1 mi
HydroLAKES / HydroSHEDS
Elevation
942 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Mud Lake
Compare lakeside cabins, hotels, and vacation rentals near Mud Lake in Polk County, Wisconsin — 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 readings cover nutrients and algae, not lodging. Cabins and rentals around Mud Lake are listed below.
Top-rated places to stay near Mud Lake
Prices for Oct 16–18, 4 adults. Change dates on the map below.
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
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Fish Species
Click a species to see every lake where it is documented.
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 (2020–2025).
Water clarity
Stable6 years
Phosphorus
Improving-0.65 µg/L/yr6 years
EPA Impairment Status
Mud Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5R).
Causes of impairment
Designated uses not supporting: Aquatic life, Recreation.
Source: EPA ATTAINS assessment unit WI10004943 · Official waterbody report
Nearby Lakes in Polk County
Frequently asked questions about Mud Lake
Where is Mud Lake?
- Mud Lake is a lake in Polk County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Mud Lake?
- Mud Lake in Polk County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2 ft visibility. Phosphorus: 93 µg/L. Maximum depth: 7 ft. Surface area: 96 acres.
Is Mud Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Mud Lake is listed impaired under Clean Water Act §303(d) (IR 5R) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Mud Lake?
- Mud Lake has a maximum depth of 7 feet. The lake covers 96 acres.
What fish are in Mud Lake?
- Fish species found in Mud Lake include Musky, Panfish, Largemouth Bass, Northern Pike. Mud Lake is located in Polk County, Wisconsin.
What did the DNR fisheries survey find at Mud Lake?
- Wisconsin DNR lists Musky as present on Mud Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Mud Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Mud Lake?
- Public access to Mud Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
6 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX6 samples · 2020
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes