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LakeQuality

Spring Lake

NR
Not yet rated
9.5 ft clear · Mesotrophic · 98 acres
Limited DataMesotrophic

Spring Lake in St. Louis County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 9.5 ft visibility. Maximum depth: 25 ft. Surface area: 98.44 acres.

Clarity
9.5 ft
Typical in August
74°F
Max depth
25 ft
Area
98 acres
Trend
Stable
Public access
Yes

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NRAlden Lake5 ft clear · St. Louis CountyView →
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Why Spring 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 Spring 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, 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 MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.

Spring Lake is a 98-acre lake in St. Louis County, Minnesota with a maximum depth of 25 feet. The lake supports 8 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-08-02. Grade methodology: LakeGrade methodology.

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Swimming Safety

Not rated

Limited data

Not rated for swimming — there is not enough monitoring data to judge this lake

Compare the safest swimming lakes near Duluth

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Water quality measurements for Spring Lake

These readings exist but do not meet the evidence bar for an A–F grade — see why.

Moderate clarity, visible to about 9.5 ft. Trophic State Index: 45.

MetricValueGrade
Water Clarity (Secchi Depth)9.5 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)45Mesotrophic

Moderate nutrients, good water quality

Where to stay near Spring Lake

Compare lakeside cabins, hotels, and vacation rentals near Spring Lake in St. Louis 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 Spring Lake

Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.

Planning a whole trip? See where to stay at Minnesota’s top lakes →

Water Temperature

Spring Lake typically sits around 74°F at the surface in August. Summer average is about 70°F. Usually warmest in Aug (about 74°F) and coldest in May (about 50°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
50°
Jun
66°
Jul
70°
Aug
74°
Sep
56°
Oct
Nov
Dec

Typical surface water temperature by month, from 25 field readings (20162025) via the EPA Water Quality Portal. See the full Spring Lake water temperature breakdown →

Lake Details

CharacteristicValue
Maximum Depth25 ft
Surface Area98 acres
Shoreline Length2.9 mi
Littoral Zone95%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
3 sq mi
Elevation
1,404 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Spring LakePublic

Fish Species

Click a species to see every graded lake where it is documented.

Fishing Spring Lake

DNR Fisheries Survey Summary

4 surveys on file from MN DNR Fisheries. Most recent: 2008-08-18 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Black Bullhead86.260.16 lb
Yellow Perch11.560.16 lb
TPM10.50
White Sucker6.272.31 lb
Pumpkinseed4.890.12 lb
Northern Pike3.101.78 lb

CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.

Length Distributions

Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.

Black Bullhead

137 fish · 48 in · 2008-08-18
7739045678

Yellow Perch

10 fish · 610 in · 2008-08-18
420678910

White Sucker

44 fish · 721 in · 2008-08-18
8408101214161820

Pumpkinseed

33 fish · 37 in · 2008-08-18
2010034567

From the 2008-08-18 survey

Spring is a 97-acre lake with 93 acres (96%) of littoral area and a maximum depth of 25 feet. The lake is located 15 miles northeast of Duluth off highway #44 and has a concrete, back-in access. Parking at the access is very limited. Walleye fingerlings, yearlings or adults have been stocked in odd years since 1999.…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Spring Lake. 3 reports on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable-0.01 m/yr6
See year-by-year chart →

EPA Impairment Status

Spring Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Mercury

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN69-0130-00 · Official waterbody report · Matched by proximity (1.29 km)

Nearby Lakes in St. Louis County

Frequently asked questions about Spring Lake

What is the water quality grade for Spring Lake?

Spring Lake in St. Louis County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 9.5 ft visibility. Maximum depth: 25 ft. Surface area: 98.44 acres.

Is Spring Lake safe to swim in?

Not rated for swimming — there is not enough monitoring data to judge this lake. Spring Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.

What is the water temperature of Spring Lake?

Spring Lake typically sits around 74°F at the surface in August, from 25 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.

How deep is Spring Lake?

Spring Lake has a maximum depth of 25 feet. The lake covers 98.44 acres.

What fish are in Spring Lake?

Fish species found in Spring Lake include black bullhead, black crappie, bluegill, northern pike, pumpkinseed, walleye, white sucker, yellow perch. Spring Lake is located in St. Louis County, Minnesota.

Are there boat ramps on Spring Lake?

Spring Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Spring Lake. Public access is listed as yes.

Where this data comes from

24 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA24 samples · 2020–2025

Analytical methods

  • Field measurement/observation, generic method
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)

Lake details from Minnesota DNR LakeFinder

Named boat-access points from the USGS National Boat Ramps inventory