Ludden Lake
Iowa County, Wisconsin56 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Ludden Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- Curly-Leaf Pondweed
- 14 ft max depth
- Public access
- Limited data
Ludden Lake in Iowa County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 1.5 ft visibility. Phosphorus: 172 µg/L. Maximum depth: 14 ft. Surface area: 56 acres.
Wisconsin DNR lists Panfish as common on Ludden Lake. DNR survey details →
Ludden Lake is a 56-acre highly nutrient-loaded hypereutrophic lake in Iowa County, Wisconsin with a maximum depth of 14 feet. Overall water quality is declining over recent sampling years. The lake supports 3 documented fish species including Panfish, Largemouth Bass, and Smallmouth Bass. Public access is available with 1 public boat landing. Compared to the 5 other monitored lakes in Iowa County, Ludden Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-05-22. Methodology: how these readings are compared.
What Ludden Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing3 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. Ludden Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Ludden 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 Ludden Lake
These are the measurements Wisconsin DNR publishes for Ludden 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 1.5 ft of visibility. Phosphorus 172 µg/L. TSI 75.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 172µg/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. | 75 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Ludden Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Ludden Lake typically sits around 62°F at the surface in October. Summer average is about 76°F. Usually warmest in Jun (about 77°F) and coldest in Mar (about 42°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (42°F) to its warmest (77°F).
Typical surface water temperature by month, from 16 field readings (2024–2025) via the EPA Water Quality Portal. See the full Ludden Lake water temperature breakdown →
Wisconsin DNR lists Panfish as common on Ludden Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Ludden Lake’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is declining. 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 1999. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Ludden Lake covering fish populations, stocking, water quality, and management. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2023Ludden Lake comprehensive survey 2023Comprehensive Survey · WI DNR · 2023 (PDF)
- 2013Ludden Lake comprehensive survey 2013Comprehensive Survey · WI DNR · 2013 (PDF)
Lake Details
Max depth
14 ft
Surface area
56 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
24 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.6 mi
HydroLAKES / HydroSHEDS
Elevation
928 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Ludden LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Ludden Lake
Compare lakeside cabins, hotels, and vacation rentals near Ludden Lake in Iowa 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 Ludden Lake are listed below.
Top-rated places to stay near Ludden 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 Ludden Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Ludden 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: Worsening
Based on 5 years of monitoring (2020–2024).
Water clarity
Stable5 years
Phosphorus
Worsening+26.5 µg/L/yr2 years
Reservoir Info (USACE NID)
Ludden Lake is a man-made reservoir impounded by the Ludden Lake (completed 1964), built primarily for recreation on the MINERAL POINT BRANCH; earth-type dam, 25 ft tall and 300 ft long.
- Surface area
- 58 ac
- Normal storage
- 303 ac-ft
- Max storage
- 700 ac-ft
- Drainage area
- 24 sq mi
- Hazard class
- Low
- Owner
- LUDDEN LAKE DAM COMMISSION
Source: USACE National Inventory of Dams, NID ID WI00069 · Operator website
EPA Impairment Status
Ludden 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 WI10008359 · Official waterbody report
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Ludden Lake under Clean Water Act (NPDES) discharge permits. 2 facilities have a reported Clean Water Act violation in the past three years.
- Mineral Point Wastewater Treatment FacilityMineral Point · 2.5 mi away · NPDES WI0024791Recent violation
- Linden Wastewater Treatment FacilityLinden · 3.7 mi away · NPDES WI0021580Recent 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.
Nearby Lakes in Iowa County
Frequently asked questions about Ludden Lake
Where is Ludden Lake?
- Ludden Lake is a lake in Iowa County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Ludden Lake?
- Ludden Lake in Iowa County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 1.5 ft visibility. Phosphorus: 172 µg/L. Maximum depth: 14 ft. Surface area: 56 acres.
Is Ludden Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Ludden 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 Ludden Lake?
- Ludden Lake typically sits around 62°F at the surface in October, from 16 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Ludden Lake?
- Ludden Lake has a maximum depth of 14 feet. The lake covers 56 acres.
What fish are in Ludden Lake?
- Fish species found in Ludden Lake include Panfish, Largemouth Bass, Smallmouth Bass. Ludden Lake is located in Iowa County, Wisconsin.
What did the DNR fisheries survey find at Ludden Lake?
- Wisconsin DNR lists Panfish as common on Ludden Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Ludden Lake’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Ludden Lake?
- Ludden Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Ludden Lake. Public access is listed as yes.
Can I fish at Ludden Lake?
- Ludden 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 Ludden Lake across LakeQuality
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Where this data comes from
43 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX43 samples · 2020–2025
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