Elmo Lake
Washington County, Minnesota257 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Elmo Lake. Here is what has been measured.
- Oligotrophic
- Impaired · Mercury
- Eurasian watermilfoil
- 140 ft max depth
- Public access
- Limited data
Elmo Lake in Washington County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11.1 ft visibility. Phosphorus: 12.5 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Maximum depth: 140 ft. Surface area: 256.82 acres.
Minnesota DNR's Targeted Survey on August 6, 2025 caught 7.40 largemouth bass per hour of electrofishing at Elmo Lake. Length samples in the latest survey that recorded them ran 14–14 inches. DNR survey details →
Elmo Lake is a 257-acre cold, clear oligotrophic lake in Washington County, Minnesota with a maximum depth of 140 feet (31-foot average). The lake supports 13 documented fish species including black crappie, bluegill, and green sunfish. Public access is available with 1 public boat landing. Compared to the 74 other monitored lakes in Washington County, Elmo Lake ranks #10 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Methodology: how these readings are compared.
Elmo Lake covers about 260 acres in Washington County. It has one public boat landing. The median ice-out date is April 8, which is when the open-water season begins. Vrbo is where to look for cabins and lake homes around Elmo Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Elmo Lake is good for
From access and monitoring records, not editorial picks.
- Clear water11.1 ft of visibility
- Boat launch1 documented ramp
- Fishing13 species recorded
- Ice seasonIce-out around Apr 8
- Deep water140 ft surveyed max depth
Swimming conditions
Readings onlyLimited data
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. Elmo Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, pFAS. Check local advisories before you swim.
Whether Elmo 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 Elmo Lake
These are the measurements Minnesota PCA publishes for Elmo 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 11.1 ft. Phosphorus 12.5 µg/L. Chlorophyll-a 1.6 µg/L. TSI 39.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 11.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 12.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 1.6µg/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. | 39 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Elmo Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Elmo Lake typically sits around 46°F at the surface in October. Summer average is about 63°F. Usually warmest in Jul (about 80°F) and coldest in Apr (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 (80°F).
Typical surface water temperature by month, from 598 field readings (2010–2025) via the EPA Water Quality Portal. See the full Elmo Lake water temperature breakdown →
Minnesota DNR's Targeted Survey on August 6, 2025 caught 7.40 largemouth bass per hour of electrofishing at Elmo Lake. Length samples in the latest survey that recorded them ran 14–14 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Elmo Lake’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
18 surveys on file from MN DNR Fisheries. Most recent: 2025-08-06 (Targeted Survey).
18 surveys on file · most recent 2025-08-06 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 22.95 | 2–7 in 2025-06-02 | 0.1 lb |
| Largemouth Bass | 11.55 | 14 in 2010-06-21 | 1.52 lb |
| Tullibee (Cisco) | 10.09 | 8–12 in 2025-06-02 | 0.51 lb |
| Northern Pike | 4.45 | 17–36 in 2025-06-02 | 3.02 lb |
| Yellow Perch | 3.72 | 5 in 2025-06-02 | 0.1 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.
Bluegill
Largemouth Bass
Tullibee (Cisco)
Northern Pike
From the 2025-08-06 survey
A targeted survey of nearshore fish species in Lake Elmo was conducted on August 6, 2025, by Lake Biological Monitoring and Assessment program staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where possible. Backpack…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Elmo Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — ElmoFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — ElmoFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — ElmoPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
140 ft
Average depth
31 ft
Surface area
257 acres
Shoreline
4.1 mi
Littoral zone
17%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
20 sq mi
HydroLAKES / HydroSHEDS
Elevation
876 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Lake ElmoPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Elmo Lake
Compare lakeside cabins, hotels, and vacation rentals near Elmo Lake in Washington 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 Elmo Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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 →
Follow Elmo Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Elmo 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: Stable
Based on 5 years of monitoring (2020–2025).
Water clarity
Stable5 years
Ice season
Typical ice-out
Apr 8
Earliest Mar 25, 2021 · Latest Apr 30, 2018
Most recent ice-out
Mar 25
2021
4 observations · Minnesota PCA ice records
Reservoir Info (USACE NID)
Elmo Lake is a man-made reservoir impounded by the Lake Elmo Regional Park (completed 1981), built primarily for flood risk reduction on the Eagle Point Lake-TR; earth-type dam, 32 ft tall.
- Surface area
- 281 ac
- Normal storage
- 2 ac-ft
- Max storage
- 140 ac-ft
- Drainage area
- 20.3 sq mi
- Hazard class
- Low
- Owner
- WD of Valley Branch
Source: USACE National Inventory of Dams, NID ID MN00915 · Operator website
EPA Impairment Status
Elmo Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN82-0106-00 · Official waterbody report
Nearby Lakes in Washington County
Frequently asked questions about Elmo Lake
Where is Elmo Lake?
- Elmo Lake is a lake in Washington County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Elmo Lake?
- Elmo Lake in Washington County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11.1 ft visibility. Phosphorus: 12.5 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Maximum depth: 140 ft. Surface area: 256.82 acres.
Is Elmo Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Elmo Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, pFAS. Check local advisories before you swim.
What is the water temperature of Elmo Lake?
- Elmo Lake typically sits around 46°F at the surface in October, from 598 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Elmo Lake?
- Elmo Lake has a maximum depth of 140 feet and an average depth of 31 feet. The lake covers 256.82 acres.
What fish are in Elmo Lake?
- Fish species found in Elmo Lake include black crappie, bluegill, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, smallmouth bass, tiger muskellunge, tullibee (cisco), walleye, white sucker, yellow perch. Elmo Lake is located in Washington County, Minnesota.
What did the DNR fisheries survey find at Elmo Lake?
- Minnesota DNR's Targeted Survey on August 6, 2025 caught 7.40 largemouth bass per hour of electrofishing at Elmo Lake. Length samples in the latest survey that recorded them ran 14–14 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Elmo Lake’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
When does Elmo Lake thaw?
- Elmo Lake typically has ice-out around Apr 8.
Are there boat ramps on Elmo Lake?
- Elmo Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lake Elmo. Public access is listed as yes.
Can I fish at Elmo Lake?
- Elmo 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 Elmo 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 Washington County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the St. Croix Watershed, ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
State Parks Near Elmo Lake
Other Lakes in Minnesota
Oligotrophic Lakes in Minnesota
Where this data comes from
38 measurements from 2 monitoring stations, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA38 samples · 2021–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Analysis of Chlorophyll in Periphyton and Plankton
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