Hay Lake
Washington County, MinnesotaView mapDirections
Minnesota PCA publishes the water-quality measurements for Hay Lake. Here is what has been measured.
- Eutrophic
- Limited data
Hay Lake in Washington County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.5 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 4.8 µg/L.
Hay Lake is a productive, nutrient-rich eutrophic lake in Washington County, Minnesota. Limited fish-species data available. No public access — the lake is private or restricted. Compared to the 74 other monitored lakes in Washington County, Hay Lake ranks #35 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-14. Methodology: how these readings are compared.
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 Hay 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 Hay Lake
These are the measurements Minnesota PCA publishes for Hay Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 3.5 ft. Phosphorus 30 µg/L. Chlorophyll-a 4.8 µg/L. TSI 53.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 30µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 4.8µg/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. | 53 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Hay Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Hay Lake typically sits around 50°F at the surface in October. Summer average is about 76°F. Usually warmest in Jul (about 78°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 (78°F).
Typical surface water temperature by month, from 86 field readings (2010–2024) via the EPA Water Quality Portal. See the full Hay Lake water temperature breakdown →
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Stays near Hay Lake
Compare lakeside cabins, hotels, and vacation rentals near Hay 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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Fishing Hay Lake
Nearby Lakes in Washington County
Frequently asked questions about Hay Lake
Where is Hay Lake?
- Hay 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 Hay Lake?
- Hay Lake in Washington County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.5 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 4.8 µg/L.
Is Hay 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 Hay Lake?
- Hay Lake typically sits around 50°F at the surface in October, from 86 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
Can I fish at Hay Lake?
- Public access to Hay 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 Hay Lake across LakeQuality
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Where this data comes from
28 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
MNPCA28 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.