Plaisted Lake
Plaisted Lake in Washington County, Minnesota has a water quality grade of C (Fair). Water clarity: 7.3 ft visibility. Phosphorus: 25 µg/L. Chlorophyll-a (algae): 3.1 µg/L.
- Clarity
- 7.3 ft
- Typical in August
- 74°F
- Max depth
- ~34 ft est.
- Type
- Mesotrophic
- Public access
- No
- Ice-out
- Apr 6
- Open water
- 234 days
Next lake in Washington County
Plaisted Lake is a mesotrophic lake in Washington County, Minnesota with an estimated average depth of about 34 feet. Water quality is graded C based on 2 sampling years through 2024. Limited fish-species data available. No public access — the lake is private or restricted. Compared to the 74 other monitored lakes in Washington County, Plaisted Lake ranks #39 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-21. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Moderate clarity, visible to about 7.3 ft. Phosphorus level: 25 µg/L. Chlorophyll-a: 3.1 µg/L. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.3 ft | Not graded |
| Phosphorus | 25 µg/L | Fair |
| Chlorophyll-a (Algae) | 3.1 µg/L | Good |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Plaisted Lake
Compare lakeside cabins, hotels, and vacation rentals near Plaisted 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.
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Water Temperature
Plaisted Lake typically sits around 74°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 75°F) and coldest in Apr (about 49°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 134 field readings (2010–2024) via the EPA Water Quality Portal. See the full Plaisted Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~34 ft est. |
| Average Depth | ~7 ft est. |
| Public Access | No |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Minnesota has not published bathymetry for Plaisted Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Fishing Plaisted 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.
Ice Season
Historical ice data from Minnesota DNR (18 observations).
Estimated open water season: 234 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-03-19 (2012) | 2013-04-29 (2013) |
| Ice-In | 2019-11-08 (2019) | 2017-12-20 (2017) |
Most recent ice-out: 2023-04-20
EPA Impairment Status
Plaisted Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN82-0151-00 · Official waterbody report · Matched by proximity (1.53 km)
County Ranking
Ranked #39 of 75 lakes in Washington County
Nearby Lakes in Washington County
Frequently asked questions about Plaisted Lake
What is the water quality grade for Plaisted Lake?
- Plaisted Lake in Washington County, Minnesota has a water quality grade of C (Fair). Water clarity: 7.3 ft visibility. Phosphorus: 25 µg/L. Chlorophyll-a (algae): 3.1 µg/L.
Is Plaisted Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Plaisted Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 3.1 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Plaisted Lake?
- Plaisted Lake typically sits around 74°F at the surface in August, from 134 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
How deep is Plaisted Lake?
- No published bathymetric survey covers Plaisted Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 34 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
When does Plaisted Lake thaw?
- Plaisted Lake typically has ice-out around Apr 6. Ice typically forms around Nov 26. The open water season is approximately 234 days.
Explore Plaisted Lake across LakeGrade
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Where this data comes from
56 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
MNPCA56 samples · 2024
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Analysis of Chlorophyll in Periphyton and Plankton
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
Ice data from Minnesota DNR Climate