Weallup Lake
Snohomish County, WashingtonView mapDirections
Washington Ecology publishes the water-quality measurements for Weallup Lake. Here is what has been measured.
- Eutrophic
- Limited data
Weallup Lake in Snohomish County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Phosphorus: 40 µg/L.
Weallup Lake is a productive, nutrient-rich eutrophic lake in Snohomish County, Washington. Overall water quality is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, WA Ecology, last sampled 2019-04-29. Methodology: how these readings are compared.
If you are planning to stay, you can search lake houses and cabins around Weallup Lake on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
Swimming conditions
Readings onlyLimited data
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. Check local advisories before you swim.
Whether Weallup 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 Weallup Lake
These are the measurements Washington Ecology publishes for Weallup 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 40 µg/L. TSI 57.
| 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 | 40µg/L | Fair GoodFairPoor |
| 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. | 57 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Weallup Lake
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Stays near Weallup Lake
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Fishing Weallup Lake
Water quality readings over time
2 seasons of samples on record (2012–2018). Calling a direction takes at least 4 years of the same measurement.
Phosphorus
Worsening+2.92 µg/L/yr2 years
Nearby Lakes in Snohomish County
Frequently asked questions about Weallup Lake
Where is Weallup Lake?
- Weallup 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 Weallup Lake?
- Weallup Lake in Snohomish County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Phosphorus: 40 µg/L.
Is Weallup Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Weallup Lake across LakeQuality
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Where this data comes from
22 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_WQX22 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.