Turtle Lake
Turtle Lake in Walworth County, Wisconsin has a water quality grade of B (Good). Water clarity: 11 ft visibility. Phosphorus: 15.2 µg/L. Maximum depth: 30 ft. Surface area: 141 acres.
Wisconsin DNR lists Panfish as present on Turtle Lake. DNR survey details →
- Clarity
- 11 ft
- Typical in August
- 78°F
- Max depth
- 30 ft
- Area
- 141 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
Next lake in Walworth County
Swipe left or right on this bar to open the next or previous lake.
Turtle Lake is a 141-acre mesotrophic lake in Walworth County, Wisconsin with a maximum depth of 30 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is improving 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 18 other monitored lakes in Walworth County, Turtle Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-23. Grade methodology: LakeQuality methodology.
Watch Turtle Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Grade onlyLow 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
Water Quality Grade: B (Good)
Good clarity, visible to about 11 ft. Phosphorus level: 15.2 µg/L. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 11 ft | Not graded |
| Phosphorus | 15.2 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Turtle Lake
Compare lakeside cabins, hotels, and vacation rentals near Turtle Lake in Walworth 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 Turtle 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
Turtle Lake typically sits around 78°F at the surface in August. Summer average is about 79°F. Usually warmest in Jun (about 80°F) and coldest in Mar (about 46°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 18 field readings (2024–2026) via the EPA Water Quality Portal. See the full Turtle Lake water temperature breakdown →
Wisconsin DNR lists Panfish as present on Turtle Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Turtle Lake B from EPA Water Quality Portal chemistry, 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 1993. 1 station on file (most recent sample 2026).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Turtle 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).
- 2021Turtle Lake spring shocking survey, 2017, 2021Spring Shocking Survey · WI DNR · 2021 (PDF)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 30 ft |
| Surface Area | 141 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Turtle 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 Turtle 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 data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.143 m/yr | 7 |
| Phosphorus | ↑ Improving | -0.84 µg/L/yr | 7 |
EPA Impairment Status
Turtle Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10006234 · Official waterbody report
County Ranking
Ranked #9 of 19 lakes in Walworth County
Nearby Lakes in Walworth County
Frequently asked questions about Turtle Lake
Where is Turtle Lake?
- Turtle Lake is a lake in Walworth County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Turtle Lake?
- Turtle Lake in Walworth County, Wisconsin has a water quality grade of B (Good). Water clarity: 11 ft visibility. Phosphorus: 15.2 µg/L. Maximum depth: 30 ft. Surface area: 141 acres.
Is Turtle Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Turtle Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Turtle Lake?
- Turtle Lake typically sits around 78°F at the surface in August, from 18 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Turtle Lake?
- Turtle Lake has a maximum depth of 30 feet. The lake covers 141 acres.
What fish are in Turtle Lake?
- Fish species found in Turtle Lake include Panfish, Largemouth Bass, Northern Pike. Turtle Lake is located in Walworth County, Wisconsin.
What did the DNR fisheries survey find at Turtle Lake?
- Wisconsin DNR lists Panfish as present on Turtle Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Turtle Lake B from EPA Water Quality Portal chemistry, 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 Turtle Lake?
- Turtle Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Turtle Lake. Public access is listed as yes.
Explore Turtle Lake across LakeQuality
Fish species and top-graded lakes across Wisconsin
Fish species and best lakes in Walworth County
Species activity outlook by water temperature and season
Where to stay at Wisconsin's top lakes, each with its grade
Moderate nutrients, good water quality
Wisconsin's cleanest and most-polluted lakes, ranked
More Wisconsin Lake Rankings
State Parks Near Turtle Lake
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
Where this data comes from
86 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_WQX86 samples · 2020–2026
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
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