Saint Johns Lake
Saint Johns Lake in Kandiyohi County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 0.5 ft visibility. Phosphorus: 189 µg/L. Chlorophyll-a (algae): 140 µg/L.
- Clarity
- 0.5 ft
- Typical in August
- 74°F
- Mean depth
- ~9 ft est.
- Trend
- ↑ Improving
- Public access
- No
- Ice-out
- Apr 7
- Open water
- 227 days
Next lake in Kandiyohi County
Why Saint Johns 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 Saint Johns Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. 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.
Saint Johns Lake is a lake in Kandiyohi County, Minnesota with an estimated average depth of about 9 feet. Overall water quality is improving 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 2023-09-12. Grade methodology: LakeGrade methodology.
Watch Saint Johns Lake water quality
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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 Saint Johns Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Very murky, less than 0.5 ft of visibility. Phosphorus level: 189 µg/L. Chlorophyll-a: 140 µg/L. Trophic State Index: 82.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.5 ft | Not graded |
| Phosphorus | 189 µg/L | Not graded |
| Chlorophyll-a (Algae) | 140 µg/L | Not graded |
| Trophic State Index (TSI) | 82 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Saint Johns Lake
Compare lakeside cabins, hotels, and vacation rentals near Saint Johns Lake in Kandiyohi 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 Saint Johns Lake
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Water Temperature
Saint Johns Lake typically sits around 74°F at the surface in August. Summer average is about 75°F. Usually warmest in Jul (about 81°F) and coldest in Sep (about 58°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 32 field readings (2010–2023) via the EPA Water Quality Portal. See the full Saint Johns Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~9 ft est. |
| Public Access | No |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for Saint Johns 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 Saint Johns Lake
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.019 m/yr | 4 |
Ice Season
Historical ice data from Minnesota DNR (11 observations).
Estimated open water season: 227 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2021-03-21 (2021) | 2013-04-30 (2013) |
| Ice-In | 2006-11-17 (2006) | 2007-11-22 (2007) |
Most recent ice-out: 2022-04-12
EPA Impairment Status
Saint Johns 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 MN34-0283-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Saint Johns Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger.
- Willmar WwtpWillmar · 3.8 mi away · NPDES MN0025259Major
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 Saint Johns Lake
Saint Johns Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Kandiyohi County
Frequently asked questions about Saint Johns Lake
What is the water quality grade for Saint Johns Lake?
- Saint Johns Lake in Kandiyohi County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 0.5 ft visibility. Phosphorus: 189 µg/L. Chlorophyll-a (algae): 140 µg/L.
Is Saint Johns Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Saint Johns Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Algae concentration (chlorophyll-a) is 140 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Saint Johns Lake?
- Saint Johns Lake typically sits around 74°F at the surface in August, from 32 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
How deep is Saint Johns Lake?
- No published bathymetric survey covers Saint Johns Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 9 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
When does Saint Johns Lake thaw?
- Saint Johns Lake typically has ice-out around Apr 7. Ice typically forms around Nov 20. The open water season is approximately 227 days.
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Where this data comes from
25 measurements from 1 monitoring station, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA25 samples · 2020–2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate