Lost Lake
Lost Lake in Polk County, Wisconsin has a water quality grade of C (Fair). Water clarity: 6 ft visibility. Phosphorus: 25.4 µg/L.
- Clarity
- 6 ft
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
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Lost Lake is a productive, nutrient-rich eutrophic lake in Polk County, Wisconsin. Water quality is graded C based on 1 sampling years through 2024. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 54 other monitored lakes in Polk County, Lost Lake ranks #30 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-09-10. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLimited data
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Murky, only visible to about 6 ft. Phosphorus level: 25.4 µg/L. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6 ft | Not graded |
| Phosphorus | 25.4 µg/L | Fair |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Lost Lake
Compare lakeside cabins, hotels, and vacation rentals near Lost Lake in Polk 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 Lost Lake
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Recreation & Access
- VossPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Lost Lake
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.279 m/yr | 6 |
| Phosphorus | ↓ Declining | +4.55 µg/L/yr | 4 |
County Ranking
Ranked #30 of 55 lakes in Polk County
Nearby Lakes With Higher Grades
Lost Lake holds Grade C. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Polk County
Frequently asked questions about Lost Lake
Where is Lost Lake?
- Lost Lake is a lake in Polk County, Wisconsin. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lost Lake?
- Lost Lake in Polk County, Wisconsin has a water quality grade of C (Fair). Water clarity: 6 ft visibility. Phosphorus: 25.4 µg/L.
Is Lost Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Lost Lake has a water quality grade of C (Fair). Always check local health department advisories before swimming.
Are there boat ramps on Lost Lake?
- Lost Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Voss. Public access is listed as yes.
Explore Lost Lake across LakeQuality
Fish species and top-graded lakes across Wisconsin
Fish species and best lakes in Polk 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
Wisconsin's cleanest and most-polluted lakes, ranked
More Wisconsin Lake Rankings
State Parks Near Lost Lake
Other Grade C Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Where this data comes from
12 measurements from 2 monitoring stations, 2023–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX12 samples · 2023–2024
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory