Otter Lake
Ramsey County, Minnesota302 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Otter Lake. Here is what has been measured.
- Mesotrophic
- Impaired · Mercury
- Eurasian watermilfoil
- 21 ft max depth
- Public access
Otter Lake in Ramsey County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11.5 ft visibility. Phosphorus: 22 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 21 ft. Surface area: 302.21 acres.
Minnesota DNR's Standard Survey on June 10, 2019 caught 0.50 walleye per gill net at Otter Lake. DNR survey details →
Otter Lake is a 302-acre mesotrophic lake in Ramsey County, Minnesota with a maximum depth of 21 feet (6-foot average). 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 with 1 public boat landing. Compared to the 43 other monitored lakes in Ramsey County, Otter Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-11. Methodology: how these readings are compared.
What Otter Lake is good for
From access and monitoring records, not editorial picks.
- Clear water11.5 ft of visibility
- Boat launch1 documented ramp
- Fishing12 species recorded
- Ice seasonIce-out around Apr 3
Swimming conditions
Readings onlyLow algae
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.
Nutrient and algae readings are not a swimming clearance. Otter Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Otter 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 Otter Lake
These are the measurements Minnesota PCA publishes for Otter Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 11.5 ft. Phosphorus 22 µg/L. Chlorophyll-a 2.7 µg/L. TSI 44.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 11.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 22µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 2.7µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 44 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Otter Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Otter Lake typically sits around 50°F at the surface in October. Summer average is about 70°F. Usually warmest in Jul (about 72°F) and coldest in Mar (about 40°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (40°F) to its warmest (72°F).
Typical surface water temperature by month, from 491 field readings (2010–2025) via the EPA Water Quality Portal. See the full Otter Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Otter Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (151,356 cells/mL) on November 16, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Minnesota DNR's Standard Survey on June 10, 2019 caught 0.50 walleye per gill net at Otter Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Otter 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
8 surveys on file from MN DNR Fisheries. Most recent: 2019-06-10 (Standard Survey).
8 surveys on file · most recent 2019-06-10 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Bullhead | 25.41 | 4–11 in 2019-06-10 | 0.35 lb |
| Bluegill | 12.46 | 3–8 in 2019-06-10 | 0.21 lb |
| Brown Bullhead | 10.83 | 0.53 lb | |
| Northern Pike | 8.84 | 9–28 in 2019-06-10 | 1.49 lb |
| Hybrid Sunfish | 3.59 | 3–9 in 2019-06-10 | 0.26 lb |
| Pumpkinseed | 2.85 | 3–6 in 2019-06-10 | 0.18 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
Bluegill
Northern Pike
Hybrid Sunfish
From the 2019-06-10 survey
Otter Lake is a 332 acre highly fertile lake assigned to lake class 39. The maximum depth is 21 feet but the vast majority of the lake is 15 feet or shallower. The lack of deep water habitat has resulted in this lake being historically susceptible to winter kills. An aeration system was installed in 2002 and is…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Otter Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — OtterFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — OtterFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — OtterPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
21 ft
Average depth
6 ft
Surface area
302 acres
Shoreline
4.2 mi
Littoral zone
99%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
9 sq mi
HydroLAKES / HydroSHEDS
Elevation
896 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Bald Eagle-Otter Lake Regional ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Otter Lake
Compare lakeside cabins, hotels, and vacation rentals near Otter 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.
Top-rated places to stay near Otter 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 →
Follow Otter Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Otter 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
Stable-0.17 µg/L/yr6 years
Chlorophyll-a
Improving-0.6 µg/L/yr6 years
Ice season
Typical ice-out
Apr 3
Earliest Mar 7, 2000 · Latest Apr 29, 2018
Typical ice-in
Nov 14
Earliest Nov 9, 2019 · Latest Dec 10, 2017
Most recent ice-out
Mar 27
2026
37 observations · Minnesota PCA ice records
EPA Impairment Status
Otter 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: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN02-0003-00 · Official waterbody report
Nearby Lakes in Ramsey County
Frequently asked questions about Otter Lake
Where is Otter Lake?
- Otter 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 Otter Lake?
- Otter Lake in Ramsey County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11.5 ft visibility. Phosphorus: 22 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 21 ft. Surface area: 302.21 acres.
Is Otter Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Otter Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
What is the water temperature of Otter Lake?
- Otter Lake typically sits around 50°F at the surface in October, from 491 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Otter Lake?
- Otter Lake has a maximum depth of 21 feet and an average depth of 6 feet. The lake covers 302.21 acres.
What fish are in Otter Lake?
- Fish species found in Otter Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, yellow bullhead. Otter Lake is located in Ramsey County, Minnesota.
What did the DNR fisheries survey find at Otter Lake?
- Minnesota DNR's Standard Survey on June 10, 2019 caught 0.50 walleye per gill net at Otter Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Otter 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 Otter Lake thaw?
- Otter Lake typically has ice-out around Apr 3. Ice typically forms around Nov 14. The open water season is approximately 225 days.
Does Otter Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Otter Lake (clouds, ice, or an off-season gap). The most recent reading was high (151,356 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Otter Lake?
- Otter Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Bald Eagle-Otter Lake Regional Park. Public access is listed as yes.
Can I fish at Otter Lake?
- Otter Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. 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 Otter Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Ramsey County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
State Parks Near Otter Lake
Other Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Where this data comes from
295 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA295 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2130 B ~ Nephelometric Method
- Phosphorus by Two Reagent Colorimetry
Monitoring station identifiers (2)
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 size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate