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LakeQuality

Bullhead Lake

D
Grade D — Nutrient-rich
Nutrient-rich · #13 of 16 lakes in the county · 4.5 ft clear · Eutrophic · 70 acres
Eutrophic

Bullhead Lake in Manitowoc County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 4.5 ft visibility. Phosphorus: 70.7 µg/L. Maximum depth: 40 ft. Surface area: 70 acres.

Clarity
4.5 ft
Typical in August
61°F
Max depth
40 ft
Area
70 acres
Type
Eutrophic
Trend
Stable
Public access
Yes

Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Bullhead Lake

Next lake in Manitowoc County

DLong Lake1.9 ft clear · Manitowoc CountyView →
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Bullhead Lake is a 70-acre productive, nutrient-rich eutrophic lake in Manitowoc County, Wisconsin with a maximum depth of 40 feet. Water quality is graded D based on 1 sampling years through 2026. Water clarity is improving over recent sampling years. The lake supports 4 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available with 1 public boat landing. Compared to the 15 other monitored lakes in Manitowoc County, Bullhead Lake ranks #13 for water quality.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-27. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Elevated nutrients

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.

Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum

Compare the safest swimming lakes near Appleton

Get alerts for Bullhead Lake

Water Quality Grade: D (Nutrient-rich)

Murky, only visible to about 4.5 ft. Phosphorus level: 70.7 µg/L. Trophic State Index: 61.

MetricValueGrade
Water Clarity (Secchi Depth)4.5 ftNot graded
Phosphorus70.7 µg/LPoor
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)61Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Bullhead Lake

Compare lakeside cabins, hotels, and vacation rentals near Bullhead Lake in Manitowoc 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 grade measures nutrients and algae, not lodging — cabins and rentals around Bullhead Lake are listed below.

Top-rated places to stay near Bullhead Lake

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 →

Water Temperature

Bullhead Lake typically sits around 61°F at the surface in August. Summer average is about 65°F. Usually warmest in Jun (about 69°F) and coldest in Feb (about 39°F). These are typical values by month — not a live reading.

Jan
Feb
39°
Mar
Apr
49°
May
55°
Jun
69°
Jul
64°
Aug
61°
Sep
61°
Oct
53°
Nov
46°
Dec

Typical surface water temperature by month, from 85 field readings (20242026) via the EPA Water Quality Portal. See the full Bullhead Lake water temperature breakdown →

Lake Details

CharacteristicValue
Maximum Depth40 ft
Surface Area70 acres
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
0 sq mi
Shoreline
1.2 mi
Elevation
810 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Bullhead LakePublic

Fish Species

Click a species to see every graded lake where it is documented.

Fishing Bullhead 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.

Banded Mystery SnailCurly-Leaf PondweedEurasian Water-Milfoil

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1986. 1 station on file (most recent sample 2026).

DNR Assessment
Poor · Deep Seepage lake
Trophic State Index 66 (eutrophic) · 5-year average

Fish Species (DNR-rated)

Panfish(Abundant)Largemouth Bass(Abundant)Northern Pike(Common)Walleye(Present)

DNR Reports & Resources

Wisconsin DNR Fisheries scientists publish multi-year survey reports for Bullhead Lake covering fish populations, stocking, water quality, and management. 1 report on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

Based on 7 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.329 m/yr7
Phosphorus Declining+3.4 µg/L/yr7
See year-by-year chart →

EPA Impairment Status

Bullhead Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Nutrients (phosphorus, nitrogen)

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

Source: EPA ATTAINS assessment unit WI10000142 · Official waterbody report

Regulated Pollution Sources Nearby

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

  • Rockland SD1 Wastewater Treatment Facility
    Rockland, Town Of · 3.7 mi away · NPDES WI0022802
    Recent violation
  • Rockland Water Sewer Utilities Wwtf
    Rockland · 4.8 mi away · NPDES WI0028967
    Recent violation
  • Dallman East River Dairy Llc
    Brillion · 1 mi away · NPDES WI0063681

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.

County Ranking

Ranked #13 of 16 lakes in Manitowoc County

Nearby Lakes With Higher Grades

Bullhead Lake holds Grade D. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.

See full comparison →

Nearby Lakes in Manitowoc County

Frequently asked questions about Bullhead Lake

What is the water quality grade for Bullhead Lake?

Bullhead Lake in Manitowoc County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 4.5 ft visibility. Phosphorus: 70.7 µg/L. Maximum depth: 40 ft. Surface area: 70 acres.

Is Bullhead Lake safe to swim in?

Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Bullhead Lake has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.

What is the water temperature of Bullhead Lake?

Bullhead Lake typically sits around 61°F at the surface in August, from 85 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.

How deep is Bullhead Lake?

Bullhead Lake has a maximum depth of 40 feet. The lake covers 70 acres.

What fish are in Bullhead Lake?

Fish species found in Bullhead Lake include Panfish, Largemouth Bass, Northern Pike, Walleye. Bullhead Lake is located in Manitowoc County, Wisconsin.

Are there boat ramps on Bullhead Lake?

Bullhead Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Bullhead Lake. Public access is listed as yes.

State Parks Near Bullhead Lake

Eutrophic Lakes in Wisconsin

Where this data comes from

199 measurements from 2 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Wisconsin Department of Natural ResourcesWIDNR_WQX199 samples · 2020–2026

Analytical methods

  • Phosphorus by Colorimetry
Monitoring station identifiers (2)

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)

Fish and recreation data from Wisconsin DNR Lakes

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