Porcupine Lake
Porcupine Lake in Oconto County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 10.5 ft visibility.
- Clarity
- 10.5 ft
- Trend
- ↑ Improving
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Why Porcupine Lake has no grade
We grade a lake only when the monitoring record supports a letter: 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 Porcupine 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.
Porcupine Lake is a lake in Oconto County, Wisconsin. Overall water quality is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2023-07-31. Grade methodology: LakeQuality 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 Porcupine Lake
These readings exist but are not enough for an A–F grade — see why.
Good clarity, visible to about 10.5 ft. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Porcupine Lake
Compare lakeside cabins, hotels, and vacation rentals near Porcupine 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.
Top-rated places to stay near Porcupine Lake
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Fishing Porcupine Lake
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +2.083 m/yr | 2 |
EPA Impairment Status
Porcupine Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10000914 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Porcupine Lake under Clean Water Act (NPDES) discharge permits.
- Petersons Dairy LlcLena, Town Of · 2.8 mi away · NPDES WI0066150
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 Porcupine Lake
Porcupine Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Oconto County
Frequently asked questions about Porcupine Lake
Where is Porcupine Lake?
- Porcupine Lake is a lake in Oconto County, Wisconsin. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Porcupine Lake?
- Porcupine Lake in Oconto County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 10.5 ft visibility.
Is Porcupine Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Porcupine Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
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Where this data comes from
4 measurements from 2 monitoring stations, 2022–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX4 samples · 2022–2023
Monitoring station identifiers (2)
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)