Mud Lake
Jefferson County, Wisconsin84 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
- 22 ft max depth
- Public access
Mud Lake in Jefferson County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2.3 ft visibility. Phosphorus: 63.6 µg/L. Maximum depth: 22 ft. Surface area: 84 acres.
Wisconsin DNR lists Panfish as common on Mud Lake. DNR survey details →
Mud Lake is a 84-acre productive, nutrient-rich eutrophic lake in Jefferson County, Wisconsin with a maximum depth of 22 feet. Overall water quality is improving over recent sampling years. The lake supports 2 documented fish species including Panfish and Northern Pike. Public access is available with 1 public boat landing. Compared to the 6 other monitored lakes in Jefferson County, Mud Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-19. Methodology: how these readings are compared.
What Mud Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
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 5) 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 2.3 ft of visibility. Phosphorus 63.6 µg/L. TSI 65.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 63.6µg/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. | 65 | 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.
Water Temperature
Mud Lake typically sits around 72°F at the surface in August. Summer average is about 73°F. Usually warmest in Jun (about 73°F) and coldest in Mar (about 43°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (43°F) to its warmest (73°F).
Typical surface water temperature by month, from 23 field readings (2024–2026) via the EPA Water Quality Portal. See the full Mud Lake water temperature breakdown →
Wisconsin DNR lists Panfish as common 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 7 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. Monitored by volunteers since 2017. 1 station on file (most recent sample 2026).
Fish Species (DNR-rated)
Lake Details
Max depth
22 ft
Surface area
84 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
8 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.4 mi
HydroLAKES / HydroSHEDS
Elevation
820 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Sandhill Station State CampgroundPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Mud Lake
Compare lakeside cabins, hotels, and vacation rentals near Mud Lake in Jefferson 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 9–11, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Follow Mud Lake’s readings
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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 7 years of monitoring (2020–2026).
Water clarity
Improving7 years
Phosphorus
Stable-0.35 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 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Recreation.
Source: EPA ATTAINS assessment unit WI10006218 · Official waterbody report
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Mud Lake under Clean Water Act (NPDES) discharge permits.
- Unlimited Renewables LlcLake Mills, Town Of · 1.2 mi away · NPDES WI0065064
- Daybreak Foods Inc Creekwood FarmLake Mills · 1.2 mi away · NPDES WI0056308
- Deans Eggs Nature Link Farms LlcAztalan, Town Of · 2.7 mi away · NPDES WI0064416
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.
Nearby Lakes in Jefferson County
Frequently asked questions about Mud Lake
Where is Mud Lake?
- Mud Lake is a lake in Jefferson 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 Jefferson County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2.3 ft visibility. Phosphorus: 63.6 µg/L. Maximum depth: 22 ft. Surface area: 84 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 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Mud Lake?
- Mud Lake typically sits around 72°F at the surface in August, from 23 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Mud Lake?
- Mud Lake has a maximum depth of 22 feet. The lake covers 84 acres.
What fish are in Mud Lake?
- Fish species found in Mud Lake include Panfish, Northern Pike. Mud Lake is located in Jefferson County, Wisconsin.
What did the DNR fisheries survey find at Mud Lake?
- Wisconsin DNR lists Panfish as common 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 7 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
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 Sandhill Station State Campground. Public access is listed as yes.
Can I fish at Mud Lake?
- Mud Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. 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.
Explore Mud Lake across LakeQuality
Fish species and the cleanest lakes across Wisconsin
Fish species and best lakes in Jefferson County
Species activity outlook by water temperature and season
Where to stay at Wisconsin's top lakes, each with its readings
Wisconsin's cleanest lakes, ranked on agency measurements
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State Parks Near Mud Lake
Other Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Where this data comes from
45 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX45 samples · 2020–2026
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory