Posey Lake
Lenawee County, Michigan150 acresView mapDirections
EGLE publishes the water-quality measurements for Posey Lake. Here is what has been measured.
- 45 ft max depth
- Limited data
Posey Lake in Lenawee County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 5 ft visibility. Maximum depth: 45 ft. Surface area: 150 acres.
Posey Lake is a 150-acre lake in Lenawee County, Michigan with a maximum depth of 45 feet. Phosphorus level is declining over recent sampling years. The lake supports 7 documented fish species including Bluegill, Common carp, and Golden redhorse.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2022-09-16. Methodology: how these readings are compared.
Posey Lake covers about 150 acres in Lenawee County. For a place on the water, look through cabin and lake-house rentals near Posey Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Posey Lake is good for
From access and monitoring records, not editorial picks.
- Fishing7 species recorded
- Deep water45 ft surveyed max depth
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Posey Lake is safe to swim in today is a call for the Michigan Department of Environment, Great Lakes, and Energy (EGLE) and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Posey Lake
These are the measurements EGLE publishes for Posey 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 ft. TSI 54.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading 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. | 54 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Posey Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
45 ft
Surface area
150 acres
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Stays near Posey Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Posey Lake
Water Quality Trend: Stable
Based on 7 years of monitoring (2016–2023).
Water clarity
Stable7 years
Phosphorus
Worsening+0.92 µg/L/yr7 years
Chlorophyll-a
Improving-4.1 µg/L/yr2 years
Reservoir Info (USACE NID)
Posey Lake is a man-made reservoir impounded by the Posey Lake Level Control Structure (completed 1955), built primarily for recreation on the Posey Lake Drain; gravity-type dam, 7 ft tall and 15 ft long.
- Surface area
- 150 ac
- Normal storage
- 190 ac-ft
- Max storage
- 715 ac-ft
- Drainage area
- 0 sq mi
- Hazard class
- Low
- Owner
- Lenawee County Drain Commissioner
Source: USACE National Inventory of Dams, NID ID MI02265 · Operator website
Regulated Pollution Sources Nearby
5 EPA-permitted facilities operate within about 5 miles of Posey Lake under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.
- Hartland Farms-CafoClayton · 1.3 mi away · NPDES MI0057536Recent violation
- Bakerlads Farm-CafoClayton · 3.8 mi away · NPDES MI0059009Recent violation
- Hudson WwtpHudson · 4.1 mi away · NPDES MI0021377Recent violation
- Hartland Farms, IncClayton · 1.3 mi away · NPDES MIA000002
- Bakerlads FarmsClayton · 3.9 mi away · NPDES MIA000014
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 Lenawee County
Frequently asked questions about Posey Lake
Where is Posey Lake?
- Posey Lake is a lake in Lenawee County, Michigan. Its water-quality measurements are published by EGLE and shown on this page as reported.
What is the water quality of Posey Lake?
- Posey Lake in Lenawee County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 5 ft visibility. Maximum depth: 45 ft. Surface area: 150 acres.
Is Posey Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Posey Lake?
- Posey Lake has a maximum depth of 45 feet. The lake covers 150 acres.
What fish are in Posey Lake?
- Fish species found in Posey Lake include Bluegill, Common carp, Golden redhorse, Largemouth bass, Pumpkinseed, White sucker, Yellow bullhead. Posey Lake is located in Lenawee County, Michigan.
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Where this data comes from
73 measurements from 1 monitoring station, 2016–2022. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- North American Lake Management Society
NALMS73 samples · 2016–2022
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)