Gaystock Lake
Carver County, MinnesotaView mapDirections
Minnesota PCA publishes the water-quality measurements for Gaystock Lake. Here is what has been measured.
- Impaired · Nutrients (phosphorus, nitrogen)
- Limited data
Gaystock Lake in Carver County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 0.7 ft visibility. Phosphorus: 236 µg/L. Chlorophyll-a (algae): 78.3 µg/L.
Gaystock Lake is a lake in Carver County, Minnesota. Limited fish-species data available. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-10-05. Methodology: how these readings are compared.
Swimming conditions
No readingRecreation use not supported
Nutrient and algae readings are not a swimming clearance. Gaystock Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Gaystock 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 Gaystock Lake
These are the measurements Minnesota PCA publishes for Gaystock Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 0.7 ft of visibility. Phosphorus 236 µg/L. Chlorophyll-a 78.3 µg/L. TSI 80.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 0.7ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 236µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 78.3µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 80 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Gaystock Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Gaystock Lake typically sits around 63°F at the surface in October. Summer average is about 71°F. Usually warmest in Aug (about 77°F) and coldest in Oct (about 63°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (63°F) to its warmest (77°F).
Typical surface water temperature by month, from 20 field readings (2022–2022) via the EPA Water Quality Portal. See the full Gaystock Lake water temperature breakdown →
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Stays near Gaystock Lake
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Fishing Gaystock Lake
EPA Impairment Status
Gaystock 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: Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN10-0031-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Gaystock Lake under Clean Water Act (NPDES) discharge permits.
- CarverCarver · 2.7 mi away · NPDES MN0053457
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Carver County
Frequently asked questions about Gaystock Lake
Where is Gaystock Lake?
- Gaystock Lake is a lake in Carver County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Gaystock Lake?
- Gaystock Lake in Carver County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 0.7 ft visibility. Phosphorus: 236 µg/L. Chlorophyll-a (algae): 78.3 µg/L.
Is Gaystock Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Gaystock Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Gaystock Lake?
- Gaystock Lake typically sits around 63°F at the surface in October, from 20 EPA Water Quality Portal field readings (2022–2022). That is a typical value for the month, not a live reading.
Can I fish at Gaystock Lake?
- Public access to Gaystock 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.
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Where this data comes from
8 measurements from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA8 samples · 2022
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)