Pentwater Lake
Oceana County, Michigan485 acresView mapDirections
EGLE publishes the water-quality measurements for Pentwater Lake. Here is what has been measured.
- Limited data
Pentwater Lake in Oceana County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 6.5 ft visibility. Surface area: 484.7 acres.
Pentwater Lake is a 485-acre lake in Oceana County, Michigan. Overall water quality is improving over recent sampling years. The lake supports 1 documented fish species including Brown trout.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2022-09-30. Methodology: how these readings are compared.
Pentwater Lake covers about 480 acres in Oceana County. If you are planning to stay, you can search lake houses and cabins around Pentwater Lake on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Pentwater 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 Pentwater Lake
These are the measurements EGLE publishes for Pentwater 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 6.5 ft. TSI 50.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 6.5ft | 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. | 50 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Pentwater Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
485 acres
No bathymetric survey has been published for Pentwater Lake, so its depth is not documented here.
Stays via Stay22
Stays near Pentwater Lake
Compare lakeside cabins, hotels, and vacation rentals near Pentwater Lake in Oceana 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.
Top-rated places to stay near Pentwater Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Pentwater Lake
Water Quality Trend: Improving
Based on 8 years of monitoring (2016–2023).
Water clarity
Improving8 years
Phosphorus
Improving-0.71 µg/L/yr6 years
Chlorophyll-a
Worsening+0.79 µg/L/yr7 years
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Pentwater Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Pentwater CwpPentwater · 0.7 mi away · NPDES MI0058875Recent violation
- Blarney Castle OilHart · 3.4 mi away · NPDES MIG080727
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 Oceana County
Frequently asked questions about Pentwater Lake
Where is Pentwater Lake?
- Pentwater Lake is a lake in Oceana County, Michigan. Its water-quality measurements are published by EGLE and shown on this page as reported.
What is the water quality of Pentwater Lake?
- Pentwater Lake in Oceana County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 6.5 ft visibility. Surface area: 484.7 acres.
Is Pentwater Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What fish are in Pentwater Lake?
- Fish species found in Pentwater Lake include Brown trout. Pentwater Lake is located in Oceana County, Michigan.
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Where this data comes from
80 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
NALMS80 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)