Deschutes River Arm Lake
Jefferson County, OregonView mapDirections
Nutrients and algae run above the regional average.
↓ down from B at the last regrade
- Mesotrophic
- Impaired · Algal growth
- #4 of 14 in the county
Deschutes River Arm Lake in Jefferson County, Oregon has a water quality grade of D (Nutrient-rich). Water clarity: 4.6 ft visibility. Phosphorus: 60 µg/L. Chlorophyll-a (algae): 4.4 µg/L.
- Clarity
- 4.6 ft
- Type
- Mesotrophic
- Phosphorus
- 60 µg/L
- Chlorophyll-a
- 4.4 µg/L
- Trend
- ↑ Improving
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Stays near Deschutes River Arm Lake
Compare lakeside cabins, hotels, and vacation rentals near Deschutes River Arm Lake in Jefferson County, Oregon — 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 Deschutes River Arm Lake are listed below.
Top-rated places to stay near Deschutes River Arm Lake
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Deschutes River Arm Lake is a mesotrophic lake in Jefferson County, Oregon. Water quality is graded D based on 1 sampling years through 2025. Overall water quality is improving over recent sampling years. Compared to the 13 other monitored lakes in Jefferson County, Deschutes River Arm Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Oregon DEQ, last sampled 2025-09-10. 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. Deschutes River Arm Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, hydrologic alteration, pH / acidity. Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
Murky, only visible to about 4.6 ft. Phosphorus 60 µg/L. Chlorophyll-a 4.4 µg/L. TSI 54. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.6 ft | Not graded |
| Phosphorus | 60 µg/L | Not graded |
| Chlorophyll-a (Algae) | 4.4 µg/L | Poor |
| Trophic State Index (TSI) | 54 | Mesotrophic |
Moderate nutrients, good water quality
Fishing Deschutes River Arm Lake
Water Quality Trend: ↑ Improving
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.063 m/yr | 2 |
| Phosphorus | ↑ Improving | -2.5 µg/L/yr | 2 |
| Chlorophyll-a | ↓ Declining | +2.63 µg/L/yr | 3 |
EPA Impairment Status
Deschutes River Arm Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit OR_LK_1707030111_02_100151 · Official waterbody report · Matched by proximity (1.53 km)
County Ranking
Ranked #4 of 14 lakes in Jefferson County
Nearby Lakes With Higher Grades
Deschutes River Arm Lake holds Grade D. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Jefferson County
Frequently asked questions about Deschutes River Arm Lake
Where is Deschutes River Arm Lake?
- Deschutes River Arm Lake is a lake in Jefferson County, Oregon. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Deschutes River Arm Lake?
- Deschutes River Arm Lake in Jefferson County, Oregon has a water quality grade of D (Nutrient-rich). Water clarity: 4.6 ft visibility. Phosphorus: 60 µg/L. Chlorophyll-a (algae): 4.4 µg/L.
Is Deschutes River Arm Lake safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Deschutes River Arm Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, hydrologic alteration, pH / acidity. Check local advisories before you swim.
Explore Deschutes River Arm Lake across LakeQuality
2 thermal springs within 21.1 mi, nearest Kahneeta Hot Springs
Species activity outlook by water temperature and season
Where to stay at Oregon's top lakes, each with its grade
Moderate nutrients, good water quality
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Where this data comes from
100 measurements from 1 monitoring station, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Department of Environmental Quality - State of Oregon
OREGONDEQ100 samples · 2021–2025
Analytical methods
- 2012 National Lakes Assessment Field Operations Manual
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 10200 H ~ Chlorophyll a-b-c Determination
- 2130 B ~ Nephelometric Method
- Standard Test Method for Determination of Turbidity Above 1 Turbidity Unit (TU) in Static Mode
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
Impairment status from EPA ATTAINS 303(d) database