Little Bitterroot Lake Center
Flathead County, MontanaView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Oligotrophic
- #16 of 44 in the county
Little Bitterroot Lake Center in Flathead County, Montana has a water quality grade of A (Excellent). Phosphorus: 4 µg/L. Chlorophyll-a (algae): 1 µg/L.
- Type
- Oligotrophic
- Phosphorus
- 4 µg/L
- Chlorophyll-a
- 1 µg/L
- Trend
- ↑ Improving
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Watch Little Bitterroot Lake Center’s letter
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Little Bitterroot Lake Center is a cold, clear oligotrophic lake in Flathead County, Montana. Water quality is graded A based on 3 sampling years through 2025. Overall water quality is improving over recent sampling years. Compared to the 43 other monitored lakes in Flathead County, Little Bitterroot Lake Center ranks #16 for water quality.
Source: EPA Water Quality Portal sampling records, Montana DEQ, last sampled 2025-08-07. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyLow algae
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 A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: A (Excellent)
No clarity data. Phosphorus 4 µg/L. Chlorophyll-a 1 µg/L. TSI 27. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 4 µg/L | Good |
| Chlorophyll-a (Algae) | 1 µg/L | Good |
| Trophic State Index (TSI) | 27 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Fishing Little Bitterroot Lake Center
Water Quality Trend: ↑ Improving
Based on 14 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +1.15 m/yr | 3 |
| Phosphorus | → Stable | +0.01 µg/L/yr | 14 |
| Chlorophyll-a | ↑ Improving | -0.06 µg/L/yr | 14 |
County Ranking
Ranked #16 of 44 lakes in Flathead County
Nearby Lakes in Flathead County
Frequently asked questions about Little Bitterroot Lake Center
Where is Little Bitterroot Lake Center?
- Little Bitterroot Lake Center is a lake in Flathead County, Montana. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Little Bitterroot Lake Center?
- Little Bitterroot Lake Center in Flathead County, Montana has a water quality grade of A (Excellent). Phosphorus: 4 µg/L. Chlorophyll-a (algae): 1 µg/L.
Is Little Bitterroot Lake Center safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Explore Little Bitterroot Lake Center across LakeQuality
Species activity outlook by water temperature and season
Where to stay at Montana's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
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Where this data comes from
36 measurements from 1 monitoring station, 2019–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Montana Volunteer Water Quality Monitoring
MTVOLWQM_WQX36 samples · 2019–2025
Analytical methods
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 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.