Demontreville Lake
Washington County, Minnesota157 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Demontreville Lake. Here is what has been measured.
- Mesotrophic
- Impaired · Mercury
- 2 aquatic invasives
- 24 ft max depth
- Public access
- Limited data
Demontreville Lake in Washington County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10.2 ft visibility. Phosphorus: 25.5 µg/L. Chlorophyll-a (algae): 11 µg/L. Maximum depth: 24 ft. Surface area: 157.06 acres.
Demontreville Lake is a 157-acre mesotrophic lake in Washington County, Minnesota with a maximum depth of 24 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 with 1 public boat landing. Compared to the 74 other monitored lakes in Washington County, Demontreville Lake ranks #45 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-08. Methodology: how these readings are compared.
Demontreville Lake covers about 160 acres in Washington County. It has one public boat landing. The median ice-out date is April 3, which is when the open-water season begins. If you are planning to stay, you can search lake houses and cabins around Demontreville Lake on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What Demontreville Lake is good for
From access and monitoring records, not editorial picks.
- Clear water10.2 ft of visibility
- Boat launch1 documented ramp
- Fishing12 species recorded
- Ice seasonIce-out around Apr 3
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. Demontreville Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Demontreville 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 Demontreville Lake
These are the measurements Minnesota PCA publishes for Demontreville 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 10.2 ft. Phosphorus 25.5 µg/L. Chlorophyll-a 11 µg/L. TSI 50.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 10.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 25.5µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 11µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 50 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Demontreville Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Demontreville Lake typically sits around 61°F at the surface in October. Summer average is about 70°F. Usually warmest in Jul (about 75°F) and coldest in Feb (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 (75°F).
Typical surface water temperature by month, from 128 field readings (2010–2024) via the EPA Water Quality Portal. See the full Demontreville Lake water temperature breakdown →
Lake Details
Max depth
24 ft
Surface area
157 acres
Shoreline
3.4 mi
Littoral zone
82%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
7 sq mi
HydroLAKES / HydroSHEDS
Elevation
922 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Lake DeMontrevillePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Demontreville Lake
Compare lakeside cabins, hotels, and vacation rentals near Demontreville 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 Demontreville 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 Demontreville Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Demontreville 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 readings over time
3 seasons of samples on record (2023–2025). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving3 years
Ice season
Typical ice-out
Apr 3
Earliest Mar 3, 2024 · Latest Apr 12, 1978
Typical ice-in
Nov 26
Earliest Nov 2, 1991 · Latest Dec 20, 2001
Most recent ice-out
Mar 3
2024
29 observations · Minnesota PCA ice records
EPA Impairment Status
Demontreville 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 MN82-0101-00 · Official waterbody report
Nearby Lakes in Washington County
Frequently asked questions about Demontreville Lake
Where is Demontreville Lake?
- Demontreville 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 Demontreville Lake?
- Demontreville Lake in Washington County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10.2 ft visibility. Phosphorus: 25.5 µg/L. Chlorophyll-a (algae): 11 µg/L. Maximum depth: 24 ft. Surface area: 157.06 acres.
Is Demontreville Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Demontreville 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 Demontreville Lake?
- Demontreville Lake typically sits around 61°F at the surface in October, from 128 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
How deep is Demontreville Lake?
- Demontreville Lake has a maximum depth of 24 feet. The lake covers 157.06 acres.
What fish are in Demontreville Lake?
- Fish species found in Demontreville Lake include black bullhead, black crappie, bluegill, brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, white crappie, yellow bullhead, yellow perch. Demontreville Lake is located in Washington County, Minnesota.
When does Demontreville Lake thaw?
- Demontreville Lake typically has ice-out around Apr 3. Ice typically forms around Nov 26. The open water season is approximately 237 days.
Are there boat ramps on Demontreville Lake?
- Demontreville Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lake DeMontreville. Public access is listed as yes.
Can I fish at Demontreville Lake?
- Demontreville 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 Demontreville Lake across LakeQuality
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Species activity outlook by water temperature and season
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Where this data comes from
42 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA42 samples · 2024
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Analysis of Chlorophyll in Periphyton and Plankton
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 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