South Long Lake
Ramsey County, Minnesota173 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for South Long Lake. Here is what has been measured.
- Eutrophic
- Impaired · Mercury
- 2 aquatic invasives
- 30 ft max depth
- Public access
South Long Lake in Ramsey County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 46 µg/L. Chlorophyll-a (algae): 22.8 µg/L. Maximum depth: 30 ft. Surface area: 172.63 acres.
Minnesota DNR's Standard Survey on August 2, 2021 caught 2.20 northern pike per gill net at South Long Lake. DNR survey details →
South Long Lake is a 173-acre productive, nutrient-rich eutrophic lake in Ramsey County, Minnesota with a maximum depth of 30 feet. Overall water quality is improving over recent sampling years. The lake supports 12 documented fish species including black bullhead, black crappie, and bluegill. Public access is available. Compared to the 43 other monitored lakes in Ramsey County, South Long Lake ranks #26 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Methodology: how these readings are compared.
What South Long Lake is good for
From access and monitoring records, not editorial picks.
- Fishing12 species recorded
- Ice seasonIce-out around Apr 10
- Deep water30 ft surveyed max depth
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Based on E. coli testing, South Long Lake occasionally exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 6.5% of 92 samples across 3 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Minnesota’s current beach and health-department advisories before swimming.
Whether South Long Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for South Long Lake
These are the measurements Minnesota PCA publishes for South Long Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 3.9 ft. Phosphorus 46 µg/L. Chlorophyll-a 22.8 µg/L. TSI 59.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 46µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 22.8µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 59 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about South Long Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
South Long Lake typically sits around 53°F at the surface in October. Summer average is about 67°F. Usually warmest in Aug (about 70°F) and coldest in Mar (about 39°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (39°F) to its warmest (70°F).
Typical surface water temperature by month, from 785 field readings (2010–2025) via the EPA Water Quality Portal. See the full South Long Lake water temperature breakdown →
Minnesota DNR's Standard Survey on August 2, 2021 caught 2.20 northern pike per gill net at South Long Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows South Long Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
11 surveys on file from MN DNR Fisheries. Most recent: 2021-08-02 (Standard Survey).
11 surveys on file · most recent 2021-08-02 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Bullhead | 85.28 | 5–9 in 2021-08-02 | 0.18 lb |
| Black Crappie | 7.86 | 4–8 in 2021-08-02 | 0.23 lb |
| Common Carp | 7.14 | 12–28 in 2021-08-02 | 2.2 lb |
| Bluegill | 5.92 | 3–7 in 2021-08-02 | 0.24 lb |
| Yellow Bullhead | 4.46 | 10–13 in 2021-08-02 | 0.45 lb |
| White Sucker | 2.27 | 9–17 in 2021-08-02 | 1.27 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
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
Black Crappie
Common Carp
Bluegill
From the 2021-08-02 survey
Long Lake is a eutrophic, 172-acre water body in Ramsey County assigned to lake class 30. It is comprised of two sub-basins lying north and south of each other with Rice Creek flowing through the northern basin. Rice Creek continues on to connect with the Mississippi River which results in some fish species in Long…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for South Long Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — LongFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — LongFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — LongPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
30 ft
Surface area
173 acres
Shoreline
3.9 mi
Littoral zone
64%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Stays via Stay22
Stays near South Long Lake
Compare lakeside cabins, hotels, and vacation rentals near South Long Lake in Ramsey 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around South Long Lake are listed below.
Top-rated places to stay near South Long Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
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Fish Species
Click a species to see every lake where it is documented.
Fishing South Long Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Improving-1.7 µg/L/yr6 years
Chlorophyll-a
Improving-0.95 µg/L/yr6 years
Ice season
Typical ice-out
Apr 10
Earliest Mar 27, 2007 · Latest Apr 28, 2013
Typical ice-in
Dec 3
Earliest Nov 25, 2008 · Latest Dec 15, 2004
Most recent ice-out
Apr 18
2014
15 observations · Minnesota PCA ice records
EPA Impairment Status
South Long Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN62-0067-02 · Official waterbody report
Nearby Lakes in Ramsey County
Frequently asked questions about South Long Lake
Where is South Long Lake?
- South Long Lake is a lake in Ramsey County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of South Long Lake?
- South Long Lake in Ramsey County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 46 µg/L. Chlorophyll-a (algae): 22.8 µg/L. Maximum depth: 30 ft. Surface area: 172.63 acres.
Is South Long Lake safe to swim in?
- Based on E. coli testing, South Long Lake occasionally exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 6.5% of 92 samples across 3 seasons. That is a historical summary of past bacteria testing, not a current reading and not a swimming clearance. Bacteria levels can spike quickly after heavy rain, so whether South Long Lake is safe to swim in today is a call for Minnesota's water agency and the county health department; check their current beach advisories before you swim.
What is the water temperature of South Long Lake?
- South Long Lake typically sits around 53°F at the surface in October, from 785 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is South Long Lake?
- South Long Lake has a maximum depth of 30 feet. The lake covers 172.63 acres.
What fish are in South Long Lake?
- Fish species found in South Long Lake include black bullhead, black crappie, bluegill, channel catfish, common carp, freshwater drum, largemouth bass, northern pike, smallmouth buffalo, walleye, white sucker, yellow bullhead. South Long Lake is located in Ramsey County, Minnesota.
What did the DNR fisheries survey find at South Long Lake?
- Minnesota DNR's Standard Survey on August 2, 2021 caught 2.20 northern pike per gill net at South Long Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows South Long Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does South Long Lake thaw?
- South Long Lake typically has ice-out around Apr 10. Ice typically forms around Dec 3. The open water season is approximately 237 days.
Can I fish at South Long Lake?
- Public access to South Long Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore South Long Lake across LakeQuality
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Where this data comes from
340 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 Water
MNPCA340 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2130 B ~ Nephelometric Method
- Turbidity by Nephelometry
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate