First Sister Lake
Washtenaw County, MichiganView mapDirections
Not enough samples to grade — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). No letter yet. Here is what we do have.
- Impaired · Mercury
- Limited data
First Sister Lake in Washtenaw County, Michigan is not rated for water quality — its monitoring record does not meet the evidence bar.
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Watch First Sister Lake’s letter
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Why First Sister Lake has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For First Sister Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by EGLE and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
First Sister Lake is a lake in Washtenaw County, Michigan. The lake supports 3 documented fish species including Bluegill, Green sunfish, and Yellow bullhead.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2022-03-20. Grade methodology: LakeQuality methodology.
What First Sister Lake is good for
From access and monitoring records, not editorial picks.
- Fishing3 species recorded
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. First Sister Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Water quality measurements for First Sister Lake
These readings exist but are not enough for an A–F grade — see why.
No clarity data.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples |
Fish Species
Click a species to see every graded lake where it is documented.
Fishing First Sister Lake
EPA Impairment Status
First Sister Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MI040900050308-02 · Official waterbody report · Matched by proximity (0.52 km)
Regulated Pollution Sources Nearby
15 EPA-permitted facilities operate within about 5 miles of First Sister Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 7 facilities have a reported Clean Water Act violation in the past three years.
- Ann Arbor MS4Ann Arbor · 3 mi away · NPDES MI0053856Major
- Federal Mogul Corp-Tech CenterAnn Arbor · 1.3 mi away · NPDES MI0002089Recent violation
- Ntn Technical CenterAnn Arbor · 2.2 mi away · NPDES MI0041939Recent violation
- Eaton Corporation-Ann ArborAnn Arbor · 2.2 mi away · NPDES MI0004618Recent violation
- Mdot-Ann Arbor MS4Ann Arbor · 3 mi away · NPDES MI0053911Recent violation
- Sweepster Attachments LlcDexter · 3.5 mi away · NPDES MI0045934Recent violation
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.
Graded lakes near First Sister Lake
First Sister Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Washtenaw County
Frequently asked questions about First Sister Lake
Where is First Sister Lake?
- First Sister Lake is a lake in Washtenaw County, Michigan. LakeQuality has not rated this lake (UNRATED) — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
What is the water quality grade for First Sister Lake?
- First Sister Lake in Washtenaw County, Michigan is not rated for water quality — its monitoring record does not meet the evidence bar.
Is First Sister Lake safe to swim in?
- The letter is not a swimming clearance. First Sister Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
What fish are in First Sister Lake?
- Fish species found in First Sister Lake include Bluegill, Green sunfish, Yellow bullhead. First Sister Lake is located in Washtenaw County, Michigan.
Explore First Sister Lake across LakeQuality
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Where this data comes from
1 measurement from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- North American Lake Management Society
NALMS1 sample · 2022
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)