Grindle Lake
Grindle Lake in Oconto County, Wisconsin has a water quality grade of B (Good). Water clarity: 9 ft visibility. Phosphorus: 12.2 µg/L. Maximum depth: 23 ft. Surface area: 40 acres.
Wisconsin DNR lists Panfish as common on Grindle Lake. DNR survey details →
- Clarity
- 9 ft
- Typical in August
- 74°F
- Max depth
- 23 ft
- Area
- 40 acres
- Type
- Mesotrophic
- Trend
- → Stable
- Public access
- Yes
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Grindle Lake is a 40-acre mesotrophic lake in Oconto County, Wisconsin with a maximum depth of 23 feet. Water quality is graded B based on 1 sampling years through 2026. Water clarity is declining over recent sampling years. The lake supports 3 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available with 2 public boat landings. Compared to the 38 other monitored lakes in Oconto County, Grindle Lake ranks #14 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-22. Grade methodology: LakeQuality methodology.
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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)
Moderate clarity, visible to about 9 ft. Phosphorus level: 12.2 µg/L. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9 ft | Not graded |
| Phosphorus | 12.2 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Grindle Lake
Compare lakeside cabins, hotels, and vacation rentals near Grindle Lake in Oconto 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.
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Water Temperature
Grindle Lake typically sits around 74°F at the surface in August. Summer average is about 75°F. Usually warmest in Jul (about 79°F) and coldest in May (about 64°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 16 field readings (2024–2025) via the EPA Water Quality Portal. See the full Grindle Lake water temperature breakdown →
Wisconsin DNR lists Panfish as common on Grindle Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Grindle Lake B from EPA Water Quality Portal chemistry, 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 2002. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 23 ft |
| Surface Area | 40 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Grindle LakePublic
- Waupee FlowagePublic
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 Grindle 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 data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.5 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.24 µg/L/yr | 7 |
Reservoir Info (USACE NID)
Grindle Lake is a man-made reservoir impounded by the Waupee Dam (completed 1944), built primarily for fish and wildlife pond on the WAUPEE CREEK; earth-type dam, 13 ft tall and 285 ft long.
- Surface area
- 95 ac
- Normal storage
- 152 ac-ft
- Max storage
- 562 ac-ft
- Drainage area
- 11 sq mi
- Hazard class
- Significant
- Owner
- USDA FS
Source: USACE National Inventory of Dams, NID ID WI00673 · Operator website · Matched by proximity (0.59 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Grindle Lake under Clean Water Act (NPDES) discharge permits.
- Premium Waters IncRiverview · 0.4 mi away · NPDES WI0047147
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #14 of 39 lakes in Oconto County
Nearby Lakes in Oconto County
Frequently asked questions about Grindle Lake
Where is Grindle Lake?
- Grindle Lake is a lake in Oconto County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Grindle Lake?
- Grindle Lake in Oconto County, Wisconsin has a water quality grade of B (Good). Water clarity: 9 ft visibility. Phosphorus: 12.2 µg/L. Maximum depth: 23 ft. Surface area: 40 acres.
Is Grindle Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Grindle Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Grindle Lake?
- Grindle Lake typically sits around 74°F at the surface in August, from 16 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Grindle Lake?
- Grindle Lake has a maximum depth of 23 feet. The lake covers 40 acres.
What fish are in Grindle Lake?
- Fish species found in Grindle Lake include Panfish, Largemouth Bass, Northern Pike. Grindle Lake is located in Oconto County, Wisconsin.
What did the DNR fisheries survey find at Grindle Lake?
- Wisconsin DNR lists Panfish as common on Grindle Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Grindle Lake B from EPA Water Quality Portal chemistry, 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 Grindle Lake?
- Grindle Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Grindle Lake, Waupee Flowage. Public access is listed as yes.
Explore Grindle Lake across LakeQuality
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Moderate nutrients, good water quality
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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
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
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