Heidmann Lake
Heidmann Lake in Kewaunee County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 15 ft visibility. Maximum depth: 34 ft. Surface area: 23 acres.
- Clarity
- 15 ft
- Max depth
- 34 ft
- Area
- 23 acres
- Trend
- ↑ Improving
- Public access
- Yes
Next lake in Kewaunee County
Why Heidmann Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Heidmann Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by WI DNR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Heidmann Lake is a 23-acre lake in Kewaunee County, Wisconsin with a maximum depth of 34 feet. Overall water quality is improving over recent sampling years. The lake supports 2 documented fish species including Largemouth Bass and Northern Pike. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-16. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Heidmann Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Crystal clear, you can see 15 ft down. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 15 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Heidmann Lake
Compare lakeside cabins, hotels, and vacation rentals near Heidmann Lake in Kewaunee 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 Heidmann Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 34 ft |
| Surface Area | 23 acres |
| Public Access | Yes |
Recreation & Access
- Heidmann Lake County ParkPublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Heidmann 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: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +3.183 m/yr | 2 |
EPA Impairment Status
Heidmann 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 WI10000326 · Official waterbody report · Matched by proximity (1.68 km)
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Heidmann Lake under Clean Water Act (NPDES) discharge permits.
- Sandway Farm LlcFranklin, Town Of · 0.7 mi away · NPDES WI0066346
- Skyline Blue AcresFranklin, Town Of · 1.7 mi away · NPDES WI0063410
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.
Graded lakes near Heidmann Lake
Heidmann Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Kewaunee County
Frequently asked questions about Heidmann Lake
What is the water quality grade for Heidmann Lake?
- Heidmann Lake in Kewaunee County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 15 ft visibility. Maximum depth: 34 ft. Surface area: 23 acres.
Is Heidmann Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Heidmann Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
How deep is Heidmann Lake?
- Heidmann Lake has a maximum depth of 34 feet. The lake covers 23 acres.
What fish are in Heidmann Lake?
- Fish species found in Heidmann Lake include Largemouth Bass, Northern Pike. Heidmann Lake is located in Kewaunee County, Wisconsin.
Are there boat ramps on Heidmann Lake?
- Heidmann Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Heidmann Lake County Park. Public access is listed as yes.
Explore Heidmann Lake across LakeGrade
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Where this data comes from
1 measurement from 1 monitoring station, 2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX1 sample · 2026
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
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory