Frenchman Reservoir
Frenchman Reservoir in Phillips County, Montana is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 570 acres.
- Area
- 570 acres
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Why Frenchman Reservoir 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 Frenchman Reservoir, no water-quality sampling on record for this lake.
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 Montana DEQ and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Frenchman Reservoir is a 570-acre lake in Phillips County, Montana.
Source: EPA Water Quality Portal sampling records, Montana DEQ, last sampled recent years. Grade methodology: LakeQuality methodology.
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Swimming Safety
Not ratedElevated nutrients
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Frenchman Reservoir
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Trophic State Index: undefined.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) |
Where to stay near Frenchman Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Frenchman Reservoir in Phillips County, Montana — 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 Frenchman Reservoir
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 570 acres |
No bathymetric survey has been published for Frenchman Reservoir, so its depth is not documented here.
Fishing Frenchman Reservoir
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Frequently asked questions about Frenchman Reservoir
Where is Frenchman Reservoir?
- Frenchman Reservoir is a lake in Phillips County, Montana. LakeQuality has not rated this lake (UNRATED) — no water-quality sampling on record for this lake.
What is the water quality grade for Frenchman Reservoir?
- Frenchman Reservoir in Phillips County, Montana is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 570 acres.
Is Frenchman Reservoir safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Frenchman Reservoir is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
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Where this data comes from
Measurements for Frenchman Reservoir come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.