Ross Lake
Snohomish County, WashingtonView mapDirections
Washington Ecology publishes the water-quality measurements for Ross Lake. Here is what has been measured.
- Limited data
Ross Lake in Snohomish County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Phosphorus: 46 µg/L.
Ross Lake is a lake in Snohomish County, Washington.
Source: EPA Water Quality Portal sampling records, WA Ecology, last sampled 2019-04-29. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Ross Lake is safe to swim in today is a call for the Washington State Department of Ecology and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Ross Lake
These are the measurements Washington Ecology publishes for Ross 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 46 µg/L. TSI 59.
| 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 | 46µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| 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. | 59 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
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Frequently asked questions about Ross Lake
Where is Ross Lake?
- Ross Lake is a lake in Snohomish County, Washington. Its water-quality measurements are published by Washington Ecology and shown on this page as reported.
What is the water quality of Ross Lake?
- Ross Lake in Snohomish County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Phosphorus: 46 µg/L.
Is Ross Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Ross Lake across LakeQuality
20.7 mi away · 120 ft
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Where this data comes from
17 measurements from 1 monitoring station, 2012–2019. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Tulalip Tribes (Tribal)
TRTUL_WQX17 samples · 2012–2019
Analytical methods
- Phosphorus, Total Ascorbic Acid Method
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.