Seeley Lake
Missoula County, MontanaView mapDirections
Montana DEQ publishes the water-quality measurements for Seeley Lake. Here is what has been measured.
- Oligotrophic
- Limited data
Seeley Lake in Missoula County, Montana has water-quality measurements published by Montana DEQ, shown here as reported. Water clarity: 15.4 ft visibility. Phosphorus: 8.9 µg/L.
Seeley Lake is a cold, clear oligotrophic lake in Missoula County, Montana. Phosphorus level is declining over recent sampling years. Compared to the 39 other monitored lakes in Missoula County, Seeley Lake ranks #8 for water quality.
Source: EPA Water Quality Portal sampling records, Montana DEQ, last sampled 2022-09-20. Methodology: how these readings are compared.
What Seeley Lake is good for
From access and monitoring records, not editorial picks.
- Clear water15.4 ft of visibility
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Seeley Lake is safe to swim in today is a call for the Montana Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Seeley Lake
These are the measurements Montana DEQ publishes for Seeley Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 15.4 ft down. Phosphorus 8.9 µg/L. TSI 37.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 15.4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 8.9µg/L | Good GoodFairPoor |
| 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. | 37 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Seeley Lake
Answers come straight from the public measurements and survey records on this page.
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Stays near Seeley Lake
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Fishing Seeley Lake
Water Quality Trend: Stable
Based on 13 years of monitoring (2012–2025).
Water clarity
Stable8 years
Phosphorus
Worsening+0.23 µg/L/yr5 years
Chlorophyll-a
Improving-1.4 µg/L/yr2 years
Nearby Lakes in Missoula County
Frequently asked questions about Seeley Lake
Where is Seeley Lake?
- Seeley Lake is a lake in Missoula County, Montana. Its water-quality measurements are published by Montana DEQ and shown on this page as reported.
What is the water quality of Seeley Lake?
- Seeley Lake in Missoula County, Montana has water-quality measurements published by Montana DEQ, shown here as reported. Water clarity: 15.4 ft visibility. Phosphorus: 8.9 µg/L.
Is Seeley Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Seeley Lake across LakeQuality
More lakes in Montana
Other Lakes in Montana
Oligotrophic Lakes in Montana
Where this data comes from
79 measurements from 1 monitoring station, 2012–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Montana Volunteer Water Quality Monitoring
MTVOLWQM_WQX79 samples · 2012–2022
Analytical methods
- Phosphorus by Colorimetry
- 4500 N C ~ Persufate Method for Total Nitrogen
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.