East Thomas Lake
Dakota County, Minnesota12 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for East Thomas Lake. Here is what has been measured.
- Eutrophic
- 19 ft max depth
East Thomas Lake in Dakota County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.6 ft visibility. Phosphorus: 27 µg/L. Chlorophyll-a (algae): 8.5 µg/L. Maximum depth: 19 ft. Surface area: 12.01 acres.
Minnesota DNR's Targeted Survey on June 23, 2022 caught 6.23 walleye per hour of electrofishing at East Thomas Lake. DNR survey details →
East Thomas Lake is a 12-acre productive, nutrient-rich eutrophic lake in Dakota County, Minnesota with a maximum depth of 19 feet (12-foot average). Overall water quality is declining over recent sampling years. The lake supports 6 documented fish species including black bullhead, black crappie, and bluegill. No public access — the lake is private or restricted. Compared to the 44 other monitored lakes in Dakota County, East Thomas Lake ranks #17 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Methodology: how these readings are compared.
What East Thomas Lake is good for
From access and monitoring records, not editorial picks.
- Fishing6 species recorded
Swimming conditions
Readings onlyModerate algae
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 East Thomas 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 East Thomas Lake
These are the measurements Minnesota PCA publishes for East Thomas 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 5.6 ft. Phosphorus 27 µg/L. Chlorophyll-a 8.5 µg/L. TSI 52.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 27µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 8.5µg/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. | 52 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about East Thomas Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
East Thomas Lake typically sits around 71°F at the surface in September. Summer average is about 77°F. Usually warmest in Jul (about 78°F) and coldest in Sep (about 71°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (71°F) to its warmest (78°F).
Typical surface water temperature by month, from 25 field readings (2010–2025) via the EPA Water Quality Portal.
Minnesota DNR's Targeted Survey on June 23, 2022 caught 6.23 walleye per hour of electrofishing at East Thomas Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows East Thomas Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
6 surveys on file from MN DNR Fisheries. Most recent: 2022-06-23 (Targeted Survey).
6 surveys on file · most recent 2022-06-23 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Largemouth Bass | 36.84 | 4–11 in 2022-06-23 | 1.03 lb |
| Black Bullhead | 23.67 | 9 in 2012-07-30 | 0.39 lb |
| Bluegill | 14.29 | 1–7 in 2012-07-30 | 0.13 lb |
| Black Crappie | 8.62 | 3–8 in 2012-07-30 | 0.15 lb |
| Golden Shiner | 6.60 | 7 in 2012-07-30 | 0.11 lb |
| Channel Catfish | 3.92 | 12–18 in 2015-07-22 | 2 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Largemouth Bass
Black Bullhead
Bluegill
Black Crappie
From the 2022-06-23 survey
Carlson Lake (19-0066-00), as it's now officially known is located in the city of Eagan. The lake drops off rather quickly to a maximum of 19 feet with approximately 26% of the surface area over 15 feet. Although an aeration system is operated (as needed) to prevent winterkill, city staff report it is not often…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for East Thomas Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — CarlsonFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — CarlsonFish Stocking History · MN DNR LakeFinder
Lake Details
Max depth
19 ft
Average depth
11.9 ft
Surface area
12 acres
Shoreline
0.6 mi
Littoral zone
70%
Share shallower than 15 ft
Public access
No
Listed by Minnesota PCA
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Fish Species
Click a species to see every lake where it is documented.
Fishing East Thomas Lake
- → East Thomas Lake fishing: DNR survey catch rates, species & stocking
- → East Thomas Lake fishing forecast & best times (species outlook + 14-day solunar calendar)
- → East Thomas Lake fishing regulations (limits, seasons, special rules)
- → Is it safe to eat fish from East Thomas Lake? (mercury & PFAS guide)
Water Quality Trend: Worsening
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Phosphorus
Worsening+1.67 µg/L/yr6 years
Chlorophyll-a
Worsening+1.11 µg/L/yr6 years
Nearby Lakes in Dakota County
Frequently asked questions about East Thomas Lake
Where is East Thomas Lake?
- East Thomas Lake is a lake in Dakota County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of East Thomas Lake?
- East Thomas Lake in Dakota County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.6 ft visibility. Phosphorus: 27 µg/L. Chlorophyll-a (algae): 8.5 µg/L. Maximum depth: 19 ft. Surface area: 12.01 acres.
Is East Thomas 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 East Thomas Lake?
- East Thomas Lake typically sits around 71°F at the surface in September, from 25 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is East Thomas Lake?
- East Thomas Lake has a maximum depth of 19 feet and an average depth of 11.9 feet. The lake covers 12.01 acres.
What fish are in East Thomas Lake?
- Fish species found in East Thomas Lake include black bullhead, black crappie, bluegill, hybrid sunfish, largemouth bass, walleye. East Thomas Lake is located in Dakota County, Minnesota.
What did the DNR fisheries survey find at East Thomas Lake?
- Minnesota DNR's Targeted Survey on June 23, 2022 caught 6.23 walleye per hour of electrofishing at East Thomas Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows East Thomas Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at East Thomas Lake?
- Public access to East Thomas 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 East Thomas Lake across LakeQuality
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Where this data comes from
112 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA112 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity, Nephelometric Method
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