Grass Lake
Shawano County, Wisconsin90 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Grass Lake. Here is what has been measured.
- Mesotrophic
- 2 aquatic invasives
- 52 ft max depth
- Public access
Grass Lake in Shawano County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 8.5 ft visibility. Phosphorus: 15.6 µg/L. Maximum depth: 52 ft. Surface area: 90 acres.
Wisconsin DNR rates Panfish and Largemouth Bass as abundant on Grass Lake. DNR survey details →
Grass Lake is a 90-acre mesotrophic lake in Shawano County, Wisconsin with a maximum depth of 52 feet. Water clarity is declining over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 20 other monitored lakes in Shawano County, Grass Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-22. Methodology: how these readings are compared.
What Grass Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing6 species recorded
- Deep water52 ft surveyed max depth
Swimming conditions
Readings onlyLow algae
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.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Grass 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 Grass Lake
These are the measurements Wisconsin DNR publishes for Grass Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 8.5 ft. Phosphorus 15.6 µg/L. TSI 45.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 8.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 15.6µg/L | Good 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. | 45 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Grass Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Grass Lake typically sits around 67°F at the surface in September. Summer average is about 80°F. Usually warmest in Jul (about 80°F) and coldest in Apr (about 54°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (54°F) to its warmest (80°F).
Typical surface water temperature by month, from 11 field readings (2024–2026) via the EPA Water Quality Portal. See the full Grass Lake water temperature breakdown →
Wisconsin DNR rates Panfish and Largemouth Bass as abundant on Grass Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Grass Lake’s water-quality measurements separately, and the water-quality trend over 7 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. Monitored by volunteers since 1987. 3 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
52 ft
Surface area
90 acres
Public access
Yes
Listed by Wisconsin DNR
Recreation & Access
- Grass LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Grass Lake
Compare lakeside cabins, hotels, and vacation rentals near Grass Lake in Shawano 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 Grass Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Grass 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 7 years of monitoring (2020–2026).
Water clarity
Worsening6 years
Phosphorus
Improving-0.29 µg/L/yr7 years
Nearby Lakes in Shawano County
Frequently asked questions about Grass Lake
Where is Grass Lake?
- Grass Lake is a lake in Shawano County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Grass Lake?
- Grass Lake in Shawano County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 8.5 ft visibility. Phosphorus: 15.6 µg/L. Maximum depth: 52 ft. Surface area: 90 acres.
Is Grass Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Grass Lake?
- Grass Lake typically sits around 67°F at the surface in September, from 11 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Grass Lake?
- Grass Lake has a maximum depth of 52 feet. The lake covers 90 acres.
What fish are in Grass Lake?
- Fish species found in Grass Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Grass Lake is located in Shawano County, Wisconsin.
What did the DNR fisheries survey find at Grass Lake?
- Wisconsin DNR rates Panfish and Largemouth Bass as abundant on Grass Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Grass Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Grass Lake?
- Grass Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Grass Lake. Public access is listed as yes.
Can I fish at Grass Lake?
- Grass Lake has 1 documented boat landing 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 Grass Lake across LakeQuality
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Where this data comes from
62 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_WQX62 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
- Total Phosphorus After Block Digestion
- 2130 B ~ Nephelometric Method
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
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory