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Pearl Lake

B
Grade B — Good
Good · #11 of 16 lakes in the county · 19 ft clear · Oligotrophic · 101 acres · from A
Oligotrophic

Pearl Lake in Waushara County, Wisconsin has a water quality grade of B (Good). Water clarity: 19 ft visibility. Phosphorus: 10.8 µg/L. Maximum depth: 45 ft. Surface area: 101 acres.

Wisconsin DNR lists Largemouth Bass as common on Pearl Lake. DNR survey details →

Clarity
19 ft
Typical in August
76°F
Max depth
45 ft
Area
101 acres
Type
Oligotrophic
Trend
Declining
Public access
Yes

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Pearl Lake is a 101-acre cold, clear oligotrophic lake in Waushara County, Wisconsin with a maximum depth of 45 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is declining over recent sampling years. The lake supports 3 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 Waushara County, Pearl Lake ranks #11 for water quality.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-05-15. Grade methodology: LakeQuality methodology.

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Swimming Safety

Grade only

Low algae

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

Compare the safest swimming lakes near Oshkosh

Get alerts for Pearl Lake

Water Quality Grade: B (Good)

Crystal clear, you can see 19 ft down. Phosphorus level: 10.8 µg/L. Trophic State Index: 37.

MetricValueGrade
Water Clarity (Secchi Depth)19 ftNot graded
Phosphorus10.8 µg/LGood
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)37Oligotrophic

Low nutrients, clear water, excellent for swimming

Where to stay near Pearl Lake

Compare lakeside cabins, hotels, and vacation rentals near Pearl Lake in Waushara 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 Pearl 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

Pearl Lake typically sits around 76°F at the surface in August. Summer average is about 77°F. Usually warmest in Jul (about 80°F) and coldest in May (about 62°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
62°
Jun
75°
Jul
80°
Aug
76°
Sep
Oct
Nov
Dec

Typical surface water temperature by month, from 10 field readings (20242025) via the EPA Water Quality Portal. See the full Pearl Lake water temperature breakdown →

DNR fisheries survey

Wisconsin DNR lists Largemouth Bass as common on Pearl Lake.

A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Pearl Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 6 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 1986. 2 stations on file (most recent sample 2025).

DNR Assessment
Excellent · Deep Seepage lake
Trophic State Index 38 (oligotrophic) · 5-year average

Fish Species (DNR-rated)

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

DNR Reports & Resources

Wisconsin DNR Fisheries scientists publish multi-year survey reports for Pearl 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).

Lake Details

CharacteristicValue
Maximum Depth45 ft
Surface Area101 acres
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
2 sq mi
Shoreline
2.1 mi
Elevation
823 ft

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

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Pearl LakePublic

Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps

Fish Species

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

Fishing Pearl 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-MilfoilHybrid Eurasian / Northern Water-MilfoilZebra Mussel

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-1.536 m/yr6
Phosphorus Declining+2.48 µg/L/yr6
See year-by-year chart →

Regulated Pollution Sources Nearby

1 EPA-permitted facility operate within about 5 miles of Pearl Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.

  • Redgranite Wastewater Treatment Facility
    Redgranite · 4.2 mi away · NPDES WI0020729
    Recent 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.

County Ranking

Ranked #11 of 16 lakes in Waushara County

Nearby Lakes in Waushara County

Frequently asked questions about Pearl Lake

Where is Pearl Lake?

Pearl Lake is a lake in Waushara County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.

What is the water quality grade for Pearl Lake?

Pearl Lake in Waushara County, Wisconsin has a water quality grade of B (Good). Water clarity: 19 ft visibility. Phosphorus: 10.8 µg/L. Maximum depth: 45 ft. Surface area: 101 acres.

Is Pearl Lake safe to swim in?

Good for swimming, clear water with low algae levels. Pearl Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.

What is the water temperature of Pearl Lake?

Pearl Lake typically sits around 76°F at the surface in August, from 10 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.

How deep is Pearl Lake?

Pearl Lake has a maximum depth of 45 feet. The lake covers 101 acres.

What fish are in Pearl Lake?

Fish species found in Pearl Lake include Panfish, Largemouth Bass, Northern Pike. Pearl Lake is located in Waushara County, Wisconsin.

What did the DNR fisheries survey find at Pearl Lake?

Wisconsin DNR lists Largemouth Bass as common on Pearl Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Pearl Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.

Are there boat ramps on Pearl Lake?

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

Oligotrophic Lakes in Wisconsin

Where this data comes from

47 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_WQX47 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

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