Rainy Lake Deep
Missoula County, MontanaView mapDirections
Not Rated: one monitoring station are on record, but they measured water clarity only. LakeQuality’s A–F method grades total phosphorus, total nitrogen, chlorophyll-a, and turbidity; clarity is shown, not scored.
- Limited data
Rainy Lake Deep in Missoula County, Montana is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 18.9 ft visibility.
- Clarity
- 18.9 ft
- Trend
- ↑ Improving
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Stays near Rainy Lake Deep
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Watch Rainy Lake Deep’s letter
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Why Rainy Lake Deep has no grade
Rainy Lake Deep has monitoring on record from one station, but only water clarity was measured. LakeQuality’s A–F letter uses total phosphorus, total nitrogen, chlorophyll-a, and turbidity against EPA National Lakes Assessment condition classes. With none of those grading measurements on record, Rainy Lake Deep is Not Rated — not an F. Its 18.9-foot median from 62 readings collected 2013–2019 is still shown as clarity, but clarity alone cannot earn a letter.
Not Rated is EPA Integrated Reporting Category 3 — insufficient information. 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.
Rainy Lake Deep is a lake in Missoula County, Montana. Overall water quality is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, Montana DEQ, last sampled 2019-09-04. Grade methodology: LakeQuality methodology.
What Rainy Lake Deep is good for
From access and monitoring records, not editorial picks.
- Clear water18.9 ft of visibility
- Camping2 public campgrounds nearby
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Check local advisories before you swim.
Water quality measurements for Rainy Lake Deep
These readings exist but are not enough for an A–F grade — see why.
Crystal clear, you can see 18.9 ft down. TSI 35.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 18.9 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 35 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
Public campgrounds near Rainy Lake Deep
- Rainy Lake Campground0.3 km
- Rainy Lake Cg0.5 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Fishing Rainy Lake Deep
Water Quality Trend: ↑ Improving
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.574 m/yr | 7 |
Graded lakes near Rainy Lake Deep
Rainy Lake Deep has no grade, but these lakes within a short drive do.
Nearby Lakes in Missoula County
Frequently asked questions about Rainy Lake Deep
Where is Rainy Lake Deep?
- Rainy Lake Deep is a lake in Missoula County, Montana. LakeQuality has not rated this lake (UNRATED) — the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity.
What is the water quality grade for Rainy Lake Deep?
- Rainy Lake Deep in Missoula County, Montana is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 18.9 ft visibility.
Is Rainy Lake Deep safe to swim in?
- The letter is not a swimming clearance. Check local advisories before you swim.
How deep is Rainy Lake Deep?
- The available depth estimate for Rainy Lake Deep is shallower than its measured water clarity, which cannot be right, so no depth is shown.
Are there campgrounds on Rainy Lake Deep?
- Rainy Lake Deep has 2 public campgrounds from USGS The National Map within 5 km, including Rainy Lake Campground, Rainy Lake Cg. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Rainy Lake Deep across LakeQuality
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Where this data comes from
62 measurements from 1 monitoring station, 2013–2019. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Montana Volunteer Water Quality Monitoring
MTVOLWQM_WQX62 samples · 2013–2019
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.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Public campgrounds from USGS The National Map Structures, within about 3 miles