Tuma Lake
Manitowoc County, WisconsinMesotrophic
Tuma Lake earns an A — every scored parameter (clarity and phosphorus) rates among the best monitored waters in Manitowoc County. clarity and phosphorus rate similarly, so there is no obvious single lever to pull on watershed management.
A TSI near 45 places Tuma Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. A maximum depth of 36 ft puts Tuma Lake in the middle of Wisconsin's depth distribution. The lake is compact at 14 acres, with partial shoreline records and little volume to buffer nutrient inputs. Among the 18 graded lakes in Manitowoc County, Tuma Lake ranks 3 — in the top quartile locally.
Eurasian watermilfoil is established at Tuma Lake, which can dampen recreational access and pressure the native plant community. The fishery is bass-led, with 3 documented species across the lake's records. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-23. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Good clarity, visible to about 10 ft. Phosphorus level: 19 µg/L. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | B |
| Phosphorus | 19 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 36 ft |
| Surface Area | 14 acres |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Tuma Lake (14-day solunar calendar)
→ Is it safe to eat fish from Tuma Lake? (mercury & PFAS guide)
→ Tuma Lake fishing regulations (limits, seasons, special rules)
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: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.3 m/yr | 6 |
| Phosphorus | ↓ Declining | +5.85 µg/L/yr | 6 |
Location
County Ranking
Ranked #3 of 18 lakes in Manitowoc County
Nearby Lakes in Manitowoc County
More Wisconsin Lake Rankings
State Parks Near Tuma Lake
Other Grade A Lakes in Wisconsin
Washington County · Clarity: 11.8 ft
Washington County · Clarity: 12.6 ft
Walworth County · Clarity: 11 ft
Waukesha County · Clarity: 11.3 ft
Walworth County · Clarity: 20.2 ft
Kenosha County · Clarity: 10 ft
Mesotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
EPA Impairment Status
Tuma 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 WI10000321 · Official waterbody report · Matched by proximity (1.19 km)
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-08-23
Monitoring stations: 1