Apple Lake
Apple Lake in St. Croix County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 2.5 ft visibility. Phosphorus: 84.9 µg/L. Maximum depth: 32 ft. Surface area: 110 acres.
Wisconsin DNR rates Panfish and Largemouth Bass as abundant on Apple Lake. DNR survey details →
- Clarity
- 2.5 ft
- Typical in August
- 77°F
- Max depth
- 32 ft
- Area
- 110 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 Apple Lake →
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Apple Lake is a 110-acre productive, nutrient-rich eutrophic lake in St. Croix County, Wisconsin with a maximum depth of 32 feet. Water quality is graded D based on 1 sampling years through 2026. Water clarity is declining 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 4 other monitored lakes in St. Croix County, Apple Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-04-22. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyElevated 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
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 2.5 ft of visibility. Phosphorus level: 84.9 µg/L. Trophic State Index: 66.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.5 ft | Not graded |
| Phosphorus | 84.9 µg/L | Poor |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Apple Lake
Compare lakeside cabins, hotels, and vacation rentals near Apple Lake in St. Croix 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 Apple Lake are listed below.
Top-rated places to stay near Apple 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
Apple Lake typically sits around 77°F at the surface in August. Summer average is about 78°F. Usually warmest in Jul (about 78°F) and coldest in Sep (about 65°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 9 field readings (2024–2025) via the EPA Water Quality Portal. See the full Apple Lake water temperature breakdown →
Wisconsin DNR rates Panfish and Largemouth Bass as abundant on Apple Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Apple Lake D from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is stable. 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. 2 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Apple 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).
- 2024Apple Lake spring survey, 2024Fisheries Survey · WI DNR · 2024 (PDF)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 32 ft |
| Surface Area | 110 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Squaw 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 Apple 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: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.219 m/yr | 5 |
| Phosphorus | ↑ Improving | -26.1 µg/L/yr | 6 |
EPA Impairment Status
Apple Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit WI10005074 · Official waterbody report
County Ranking
Ranked #4 of 5 lakes in St. Croix County
Nearby Lakes With Higher Grades
Apple Lake holds Grade D. 2 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 St. Croix County
Frequently asked questions about Apple Lake
Where is Apple Lake?
- Apple Lake is a lake in St. Croix County, Wisconsin. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Apple Lake?
- Apple Lake in St. Croix County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 2.5 ft visibility. Phosphorus: 84.9 µg/L. Maximum depth: 32 ft. Surface area: 110 acres.
Is Apple 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. Apple Lake has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.
What is the water temperature of Apple Lake?
- Apple Lake typically sits around 77°F at the surface in August, from 9 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Apple Lake?
- Apple Lake has a maximum depth of 32 feet. The lake covers 110 acres.
What fish are in Apple Lake?
- Fish species found in Apple Lake include Panfish, Largemouth Bass, Northern Pike, Walleye. Apple Lake is located in St. Croix County, Wisconsin.
What did the DNR fisheries survey find at Apple Lake?
- Wisconsin DNR rates Panfish and Largemouth Bass as abundant on Apple Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Apple Lake D from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Apple Lake?
- Apple Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Squaw Lake. Public access is listed as yes.
Explore Apple Lake across LakeQuality
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Fish species and best lakes in St. Croix County
Species activity outlook by water temperature and season
Where to stay at Wisconsin's top lakes, each with its grade
Lakes in the St. Croix Watershed, ranked by water quality
High nutrients, frequent algae, reduced clarity
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More Wisconsin Lake Rankings
State Parks Near Apple Lake
Other Grade D Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Where this data comes from
46 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_WQX46 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