Mays Lake
Washington County, Minnesota40 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Mays Lake. Here is what has been measured.
- Mesotrophic
- 25 ft max depth
- Limited data
Mays Lake in Washington County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11 ft visibility. Phosphorus: 16 µg/L. Chlorophyll-a (algae): 4.1 µg/L. Maximum depth: 25 ft. Surface area: 40.22 acres.
Mays Lake is a 40-acre mesotrophic lake in Washington County, Minnesota with a maximum depth of 25 feet. Phosphorus level is declining over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted. Compared to the 74 other monitored lakes in Washington County, Mays Lake ranks #20 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-17. Methodology: how these readings are compared.
What Mays Lake is good for
From access and monitoring records, not editorial picks.
- Clear water11 ft of visibility
- Ice seasonIce-out around Mar 20
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. Check local advisories before you swim.
Whether Mays 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 Mays Lake
These are the measurements Minnesota PCA publishes for Mays 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 ft. Phosphorus 16 µg/L. Chlorophyll-a 4.1 µg/L. TSI 44.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 11ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 16µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 4.1µg/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 Mays Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Mays Lake typically sits around 54°F at the surface in October. Summer average is about 73°F. Usually warmest in Aug (about 76°F) and coldest in Apr (about 49°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (49°F) to its warmest (76°F).
Typical surface water temperature by month, from 100 field readings (2011–2024) via the EPA Water Quality Portal. See the full Mays Lake water temperature breakdown →
Lake Details
Max depth
25 ft
Surface area
40 acres
Shoreline
1.8 mi
Littoral zone
57%
Share shallower than 15 ft
Public access
No
Listed by Minnesota PCA
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Fishing Mays Lake
Water Quality Trend: Stable
Based on 6 years of monitoring (2020–2025).
Water clarity
Stable6 years
Phosphorus
Worsening+1.75 µg/L/yr2 years
Chlorophyll-a
Improving-0.3 µg/L/yr2 years
Ice season
Typical ice-out
Mar 20
Earliest Mar 19, 2012 · Latest Apr 4, 2009
Most recent ice-out
Mar 19
2012
4 observations · Minnesota PCA ice records
Nearby Lakes in Washington County
Frequently asked questions about Mays Lake
Where is Mays Lake?
- Mays 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 Mays Lake?
- Mays Lake in Washington County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11 ft visibility. Phosphorus: 16 µg/L. Chlorophyll-a (algae): 4.1 µg/L. Maximum depth: 25 ft. Surface area: 40.22 acres.
Is Mays Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Mays Lake?
- Mays Lake typically sits around 54°F at the surface in October, from 100 EPA Water Quality Portal field readings (2011–2024). That is a typical value for the month, not a live reading.
How deep is Mays Lake?
- Mays Lake has a maximum depth of 25 feet. The lake covers 40.22 acres.
When does Mays Lake thaw?
- Mays Lake typically has ice-out around Mar 20.
Can I fish at Mays Lake?
- Public access to Mays Lake is listed as no on the lake record, so confirm before you make the trip. 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 Mays Lake across LakeQuality
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Fish species and best lakes in Washington County
Species activity outlook by water temperature and season
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Where this data comes from
48 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
MNPCA48 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
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate