Jette Lake
Lake County, MontanaView mapDirections
Nutrients and algae run above the regional average.
↓ down from A at the last regrade
- Mesotrophic
- #17 of 18 in the county
Jette Lake in Lake County, Montana has a water quality grade of D (Nutrient-rich). Phosphorus: 16.6 µg/L. Chlorophyll-a (algae): 4.7 µg/L.
- Type
- Mesotrophic
- Phosphorus
- 16.6 µg/L
- Chlorophyll-a
- 4.7 µg/L
- Trend
- ↑ Improving
Stays via Stay22
Stays near Jette Lake
Compare lakeside cabins, hotels, and vacation rentals near Jette Lake in Lake 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Jette Lake are listed below.
Top-rated places to stay near Jette Lake
Prices for Sep 11–13, 4 adults. Change dates on the map below.
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Watch Jette Lake’s letter
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Jette Lake is a mesotrophic lake in Lake County, Montana. Water quality is graded D based on 3 sampling years through 2023. Overall water quality is improving over recent sampling years. Compared to the 17 other monitored lakes in Lake County, Jette Lake ranks #17 for water quality.
Source: EPA Water Quality Portal sampling records, Montana DEQ, last sampled 2023-08-28. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyElevated nutrients
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
No clarity data. Phosphorus 16.6 µg/L. Chlorophyll-a 4.7 µg/L. TSI 45. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 16.6 µg/L | Good |
| Chlorophyll-a (Algae) | 4.7 µg/L | Poor |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Fishing Jette Lake
Water Quality Trend: ↑ Improving
Based on 12 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -1.1 m/yr | 2 |
| Phosphorus | ↑ Improving | -1.48 µg/L/yr | 11 |
| Chlorophyll-a | ↑ Improving | -0.45 µg/L/yr | 12 |
County Ranking
Ranked #17 of 18 lakes in Lake County
Nearby Lakes With Higher Grades
Jette Lake holds Grade D. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Lake County
Frequently asked questions about Jette Lake
Where is Jette Lake?
- Jette Lake is a lake in Lake County, Montana. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Jette Lake?
- Jette Lake in Lake County, Montana has a water quality grade of D (Nutrient-rich). Phosphorus: 16.6 µg/L. Chlorophyll-a (algae): 4.7 µg/L.
Is Jette Lake safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Explore Jette Lake across LakeQuality
21.9 mi away · recorded at 113°F
Species activity outlook by water temperature and season
Where to stay at Montana's top lakes, each with its grade
Moderate nutrients, good water quality
Montana's cleanest and most-polluted lakes, ranked
More Montana Lake Rankings
Other Grade D Lakes in Montana
Mesotrophic Lakes in Montana
Where this data comes from
26 measurements from 1 monitoring station, 2012–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Montana Watershed
MTWTRSHD_WQX26 samples · 2012–2023
Analytical methods
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 4500 N C ~ Persufate Method for Total Nitrogen
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.