Mud Lake
Mud Lake in Polk County, Wisconsin has a water quality grade of B (Good). Water clarity: 4.3 ft visibility. Phosphorus: 24.7 µg/L. Maximum depth: 15 ft. Surface area: 14 acres.
Wisconsin DNR lists Largemouth Bass as present on Mud Lake. DNR survey details →
- Clarity
- 4.3 ft
- Max depth
- 15 ft
- Area
- 14 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
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Mud Lake is a 14-acre productive, nutrient-rich eutrophic lake in Polk County, Wisconsin with a maximum depth of 15 feet. Water quality is graded B based on 1 sampling years through 2024. Overall water quality is improving over recent sampling years. The lake supports 1 documented fish species including Largemouth Bass. Compared to the 54 other monitored lakes in Polk County, Mud Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-09-09. Grade methodology: LakeQuality 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.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Murky, only visible to about 4.3 ft. Phosphorus level: 24.7 µg/L. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.3 ft | Not graded |
| Phosphorus | 24.7 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay 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.
Top-rated places to stay near Mud Lake
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Wisconsin DNR lists Largemouth Bass as present on Mud Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Mud Lake B from EPA Water Quality Portal chemistry, 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. 1 station on file (most recent sample 2024).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 15 ft |
| Surface Area | 14 acres |
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Mud Lake
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.07 m/yr | 6 |
| Phosphorus | ↑ Improving | -2.8 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 5R).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10005006 · Official waterbody report · Matched by proximity (1.49 km)
County Ranking
Ranked #7 of 55 lakes in Polk County
Nearby Lakes in Polk County
Frequently asked questions about Mud Lake
Where is Mud Lake?
- Mud Lake is a lake in Polk County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Mud Lake?
- Mud Lake in Polk County, Wisconsin has a water quality grade of B (Good). Water clarity: 4.3 ft visibility. Phosphorus: 24.7 µg/L. Maximum depth: 15 ft. Surface area: 14 acres.
Is Mud Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Mud Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is Mud Lake?
- Mud Lake has a maximum depth of 15 feet. The lake covers 14 acres.
What fish are in Mud Lake?
- Fish species found in Mud Lake include Largemouth Bass. Mud Lake is located in Polk County, Wisconsin.
What did the DNR fisheries survey find at Mud Lake?
- Wisconsin DNR lists Largemouth Bass as present on Mud Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Mud Lake B from EPA Water Quality Portal chemistry, 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.
Explore Mud Lake across LakeQuality
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Species activity outlook by water temperature and season
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High nutrients, frequent algae, reduced clarity
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Where this data comes from
9 measurements from 1 monitoring station, 2023–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX9 samples · 2023–2024
Analytical methods
- Phosphorus by Colorimetry
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
Fish and recreation data from Wisconsin DNR Lakes