Williamson River Outlet Lake
Klamath County, OregonView mapDirections
Oregon DEQ publishes the water-quality measurements for Williamson River Outlet Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Algal growth
Williamson River Outlet Lake in Klamath County, Oregon has water-quality measurements published by Oregon DEQ, shown here as reported. Phosphorus: 165 µg/L. Chlorophyll-a (algae): 67.9 µg/L.
Williamson River Outlet Lake is a highly nutrient-loaded hypereutrophic lake in Klamath County, Oregon. Overall water quality is declining over recent sampling years. Compared to the 16 other monitored lakes in Klamath County, Williamson River Outlet Lake ranks #10 for water quality.
Source: EPA Water Quality Portal sampling records, Oregon DEQ, last sampled 2023-09-25. Methodology: how these readings are compared.
Swimming conditions
Readings onlyRecreation use not supported
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. Williamson River Outlet Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, oxygen depletion (low DO), pH / acidity, sediment / turbidity, temperature. Check local advisories before you swim.
Whether Williamson River Outlet Lake is safe to swim in today is a call for the Oregon Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Williamson River Outlet Lake
These are the measurements Oregon DEQ publishes for Williamson River Outlet Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 165 µg/L. Chlorophyll-a 67.9 µg/L. TSI 75.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 165µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 67.9µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 75 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Williamson River Outlet Lake
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Stays via Stay22
Stays near Williamson River Outlet Lake
Compare lakeside cabins, hotels, and vacation rentals near Williamson River Outlet Lake in Klamath 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 readings cover nutrients and algae, not lodging. Cabins and rentals around Williamson River Outlet Lake are listed below.
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Fishing Williamson River Outlet Lake
Water Quality Trend: Worsening
Based on 4 years of monitoring (2020–2023).
Phosphorus
Worsening+12 µg/L/yr4 years
Chlorophyll-a
Worsening+7.49 µg/L/yr4 years
EPA Impairment Status
Williamson River Outlet Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Drinking water, Aquatic life, Fish consumption, Recreation, Other.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit OR_LK_1801020303_05_100375 · Official waterbody report
Nearby Lakes in Klamath County
Frequently asked questions about Williamson River Outlet Lake
Where is Williamson River Outlet Lake?
- Williamson River Outlet Lake is a lake in Klamath County, Oregon. Its water-quality measurements are published by Oregon DEQ and shown on this page as reported.
What is the water quality of Williamson River Outlet Lake?
- Williamson River Outlet Lake in Klamath County, Oregon has water-quality measurements published by Oregon DEQ, shown here as reported. Phosphorus: 165 µg/L. Chlorophyll-a (algae): 67.9 µg/L.
Is Williamson River Outlet Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Williamson River Outlet Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, oxygen depletion (low DO), pH / acidity, sediment / turbidity, temperature. Check local advisories before you swim.
Explore Williamson River Outlet Lake across LakeQuality
Planning a trip around Crater Lake?
Williamson River Outlet Lake is about 35 miles from Crater Lake National Park. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Crater Lake →More lakes in Oregon
Other Lakes in Oregon
Hypereutrophic Lakes in Oregon
Where this data comes from
83 measurements from 1 monitoring station, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- USGS Oregon Water Science Center
USGS-OR83 samples · 2020–2023
Analytical methods
- Nutrients, wu, WCA,persulfate,CF
- Chlorophyll a, phytoplankton
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.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database