Square Lake is a cold, clear oligotrophic lake in Oakland County, Michigan. Water quality is graded A based on 1 sampling years through 2022. Water clarity is improving over recent sampling years. The lake supports 1 documented fish species including Lake herring. Compared to the 44 other monitored lakes in Oakland County, Square Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Michigan DNR, last sampled 2022-09-09. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 23 ft down. Trophic State Index: 32.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 23 ft | A |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 32 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Square Lake
Compare lakeside cabins, hotels, and vacation rentals near Square Lake in Oakland County, Michigan — 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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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Square Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Source: USGS Nonindigenous Aquatic Species (NAS) Database. Hover a chip to see scientific name, ecological context, status, and first-observed year.
Water Quality Trend: → Stable
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +4.64 m/yr | 3 |
| Chlorophyll-a | ↓ Declining | +0.45 µg/L/yr | 2 |
Location & Depth Map
Free interactive depth-contour map of Square Lake, reaching a maximum surveyed depth of 67 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Michigan DNR.
County Ranking
Ranked #2 of 45 lakes in Oakland County
Nearby Lakes in Oakland County
Explore Square Lake across LakeGrade
Fish species and top-graded lakes across Michigan
Fish species and best lakes in Oakland County
Species activity outlook by water temperature and season
Where to stay at Michigan's top lakes, each with its grade
Low nutrients, clear water, excellent for swimming
Michigan's cleanest and most-polluted lakes, ranked
More Michigan Lake Rankings
Other Grade A Lakes in Michigan
Livingston County · Clarity: 10 ft
Lapeer County · Clarity: 14.5 ft
Livingston County · Excellent
Washtenaw County · Clarity: 11.5 ft
Washtenaw County · Clarity: 12 ft
Jackson County · Clarity: 10 ft
Oligotrophic Lakes in Michigan
More records, surveys & data sources
EPA Impairment Status
Square Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MI040900040401-12 · Official waterbody report · Matched by proximity (1.7 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
11 EPA-permitted facilities operate within about 5 miles of Square Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 5 facilities have a reported Clean Water Act violation in the past three years.
- Oakland Co-Pontiac WwtpPontiac · 3.5 mi away · NPDES MI0023825MajorRecent violation
- Racer-Pontiac Sw Det FacPontiac · 2.2 mi away · NPDES MI0056031Recent violation
- Pontiac MS4-OaklandPontiac · 2.2 mi away · NPDES MI0060086Recent violation
- Gm-Pontiac Centerpoint CampusPontiac · 2.6 mi away · NPDES MIG250478Recent violation
- Bloomfield Hills MS4-OaklandBloomfield Hills · 3.9 mi away · NPDES MI0059975Recent violation
- Gmc Truck & Bus GroupPontiac · 1.4 mi away · NPDES MIP000125
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.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2022-09-09
Monitoring stations: 1