County K Marsh Lake
Green Lake County, WisconsinView mapDirections
Wisconsin DNR publishes the water-quality measurements for County K Marsh Lake. Here is what has been measured.
- Hypereutrophic
- Public access
County K Marsh Lake in Green Lake County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Phosphorus: 140 µg/L.
County K Marsh Lake is a highly nutrient-loaded hypereutrophic lake in Green Lake County, Wisconsin. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 6 other monitored lakes in Green Lake County, County K Marsh Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-10. Methodology: how these readings are compared.
What County K Marsh Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
Swimming conditions
Readings onlyBacteria tested: low
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Based on E. coli testing, County K Marsh Lake rarely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 2.3% of 261 samples across 9 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Wisconsin’s current beach and health-department advisories before swimming.
Whether County K Marsh Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for County K Marsh Lake
These are the measurements Wisconsin DNR publishes for County K Marsh Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 140 µg/L. TSI 75.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 140µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 75 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about County K Marsh Lake
Answers come straight from the public measurements and survey records on this page.
Recreation & Access
- Dodge Memorial ParkPublic
- Fox River DrivePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near County K Marsh Lake
Compare lakeside cabins, hotels, and vacation rentals near County K Marsh Lake in Green Lake 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 readings cover nutrients and algae, not lodging. Cabins and rentals around County K Marsh Lake are listed below.
Top-rated places to stay near County K Marsh Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Fishing County K Marsh Lake
Water Quality Trend: Improving
Based on 4 years of monitoring (2023–2026).
Phosphorus
Improving-15.9 µg/L/yr4 years
Nearby Lakes in Green Lake County
Frequently asked questions about County K Marsh Lake
Where is County K Marsh Lake?
- County K Marsh Lake is a lake in Green Lake County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of County K Marsh Lake?
- County K Marsh Lake in Green Lake County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Phosphorus: 140 µg/L.
Is County K Marsh Lake safe to swim in?
- Based on E. coli testing, County K Marsh Lake rarely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 2.3% of 261 samples across 9 seasons. That is a historical summary of past bacteria testing, not a current reading and not a swimming clearance. Bacteria levels can spike quickly after heavy rain, so whether County K Marsh Lake is safe to swim in today is a call for Wisconsin's water agency and the county health department; check their current beach advisories before you swim.
Are there boat ramps on County K Marsh Lake?
- County K Marsh Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Dodge Memorial Park, Fox River Drive. Public access is listed as yes.
Can I fish at County K Marsh Lake?
- County K Marsh Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Explore County K Marsh Lake across LakeQuality
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Where this data comes from
106 measurements from 1 monitoring station, 2024–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX106 samples · 2024–2026
Analytical methods
- Phosphorus by Colorimetry
- Turbidity in Water
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Named boat-access points from the USGS National Boat Ramps inventory