Johnson Lake
Johnson Lake in Pine County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 11.3 ft visibility. Phosphorus: 11 µg/L. Chlorophyll-a (algae): 2.4 µg/L.
- Clarity
- 11.3 ft
- Trend
- ↓ Declining
- Public access
- No
Next lake in Pine County
Why Johnson 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 Johnson Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity, 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 MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Johnson Lake is a lake in Pine County, Minnesota. Overall water quality is declining over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-08-22. 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 Johnson Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Good clarity, visible to about 11.3 ft. Phosphorus level: 11 µg/L. Chlorophyll-a: 2.4 µg/L. Trophic State Index: 40.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 11.3 ft | Not graded |
| Phosphorus | 11 µg/L | Not graded |
| Chlorophyll-a (Algae) | 2.4 µg/L | Not graded |
| Trophic State Index (TSI) | 40 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Johnson Lake
Compare lakeside cabins, hotels, and vacation rentals near Johnson Lake in Pine County, Minnesota — 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 Johnson Lake
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Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fishing Johnson Lake
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Johnson Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Aquatic Plant Report — Johnson (0422)Aquatic Plant Report · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.803 m/yr | 6 |
EPA Impairment Status
Johnson 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 MN58-0067-00 · Official waterbody report · Matched by proximity (1.44 km)
Nearby Lakes in Pine County
Frequently asked questions about Johnson Lake
What is the water quality grade for Johnson Lake?
- Johnson Lake in Pine County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 11.3 ft visibility. Phosphorus: 11 µg/L. Chlorophyll-a (algae): 2.4 µg/L.
Is Johnson Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Johnson Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Algae concentration (chlorophyll-a) is 2.4 µg/L. Always check local health department advisories before swimming.
How deep is Johnson Lake?
- The available depth estimate for Johnson Lake is shallower than its measured water clarity, which cannot be right, so no depth is shown.
Explore Johnson Lake across LakeGrade
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Where this data comes from
5 measurements from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA5 samples · 2022
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2130 B ~ Nephelometric Method
- 2120 B ~ Color in Water by Visual Comparison
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
Lake size & watershed from HydroLAKES (HydroSHEDS)