Lake Inez South Hole
Missoula County, MontanaView mapDirections
Clarity, phosphorus, and algae sit in the clean band for this region.
↓ down from A at the last regrade
- Oligotrophic
- #10 of 40 in the county
- Limited data
Lake Inez South Hole in Missoula County, Montana has a water quality grade of B (Good). Water clarity: 17.8 ft visibility.
- Clarity
- 17.8 ft
- Type
- Oligotrophic
- Trend
- → Stable
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Stays near Lake Inez South Hole
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Watch Lake Inez South Hole’s letter
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Lake Inez South Hole is a cold, clear oligotrophic lake in Missoula County, Montana. Water quality is graded B based on 1 sampling years through 2021. Phosphorus level is declining over recent sampling years. Compared to the 39 other monitored lakes in Missoula County, Lake Inez South Hole ranks #10 for water quality.
Source: EPA Water Quality Portal sampling records, Montana DEQ, last sampled 2021-09-17. Grade methodology: LakeQuality methodology.
What Lake Inez South Hole is good for
From access and monitoring records, not editorial picks.
- Clear water17.8 ft of visibility
Swimming Safety
Grade onlyLimited data
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 B is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: B (Good)
Crystal clear, you can see 17.8 ft down. TSI 36. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 17.8 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 36 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Fishing Lake Inez South Hole
Water Quality Trend: → Stable
Based on 12 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.234 m/yr | 8 |
| Phosphorus | ↓ Declining | +1.54 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -0.9 µg/L/yr | 2 |
County Ranking
Ranked #10 of 40 lakes in Missoula County
Nearby Lakes With Higher Grades
Lake Inez South Hole holds Grade B. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Missoula County
Frequently asked questions about Lake Inez South Hole
Where is Lake Inez South Hole?
- Lake Inez South Hole is a lake in Missoula County, Montana. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lake Inez South Hole?
- Lake Inez South Hole in Missoula County, Montana has a water quality grade of B (Good). Water clarity: 17.8 ft visibility.
Is Lake Inez South Hole safe to swim in?
- The B is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Explore Lake Inez South Hole across LakeQuality
6.6 mi away · 90 ft
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.
Montana's cleanest and most-polluted lakes, ranked
More Montana Lake Rankings
Other Grade B Lakes in Montana
Oligotrophic Lakes in Montana
Where this data comes from
54 measurements from 1 monitoring station, 2012–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Montana Volunteer Water Quality Monitoring
MTVOLWQM_WQX54 samples · 2012–2021
Analytical methods
- 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.