Johnson Lake
Johnson Lake in Becker County, Minnesota has a water quality grade of A (Excellent). Water clarity: 9.5 ft visibility. Phosphorus: 19 µg/L. Chlorophyll-a (algae): 3.2 µg/L.
- Clarity
- 9.5 ft
- Typical in August
- 71°F
- Mean depth
- ~14 ft est.
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
Next lake in Becker County
Johnson Lake is a mesotrophic lake in Becker County, Minnesota with an estimated average depth of about 14 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 83 other monitored lakes in Becker County, Johnson Lake ranks #33 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-26. Grade methodology: LakeGrade 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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 9.5 ft. Phosphorus level: 19 µg/L. Chlorophyll-a: 3.2 µg/L. Trophic State Index: 44.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.5 ft | Not graded |
| Phosphorus | 19 µg/L | Good |
| Chlorophyll-a (Algae) | 3.2 µg/L | Good |
| Trophic State Index (TSI) | 44 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Johnson Lake
Compare lakeside cabins, hotels, and vacation rentals near Johnson Lake in Becker 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.
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Water Temperature
Johnson Lake typically sits around 71°F at the surface in August. Summer average is about 75°F. Usually warmest in Jul (about 78°F) and coldest in Sep (about 65°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 34 field readings (2010–2025) via the EPA Water Quality Portal.
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~14 ft est. |
| Public Access | Yes |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for Johnson Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Fishing Johnson Lake
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Johnson Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Aquatic Plant Report — Blackbird (1008)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — BlackbirdPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.019 m/yr | 4 |
| Phosphorus | ↑ Improving | -3 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -0.87 µg/L/yr | 4 |
County Ranking
Ranked #33 of 84 lakes in Becker County
Nearby Lakes in Becker County
Frequently asked questions about Johnson Lake
What is the water quality grade for Johnson Lake?
- Johnson Lake in Becker County, Minnesota has a water quality grade of A (Excellent). Water clarity: 9.5 ft visibility. Phosphorus: 19 µg/L. Chlorophyll-a (algae): 3.2 µg/L.
Is Johnson Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Johnson Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 3.2 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Johnson Lake?
- Johnson Lake typically sits around 71°F at the surface in August, from 34 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Johnson Lake?
- No published bathymetric survey covers Johnson Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 14 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Johnson Lake across LakeGrade
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Where this data comes from
33 measurements from 2 monitoring stations, 2022–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA32 samples · 2022–2025 - Minnesota Department of Agriculture - Pesticide Monitoring
MNDA_PESTICIDE1 sample · 2022
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity, Nephelometric Method
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder