Spearhead Lake
Skagit County, WashingtonView mapDirections
Washington Ecology publishes the water-quality measurements for Spearhead Lake. Here is what has been measured.
- Limited data
Spearhead Lake in Skagit County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Water clarity: 10.8 ft visibility. Phosphorus: 14 µg/L.
Spearhead Lake is a lake in Skagit County, Washington.
Source: EPA Water Quality Portal sampling records, WA Ecology, last sampled 2017-10-26. Methodology: how these readings are compared.
What Spearhead Lake is good for
From access and monitoring records, not editorial picks.
- Clear water10.8 ft of visibility
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Spearhead 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 Spearhead Lake
These are the measurements Washington Ecology publishes for Spearhead Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 10.8 ft. Phosphorus 14 µg/L. TSI 43.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 10.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 14µg/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. | 43 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Spearhead Lake
Answers come straight from the public measurements and survey records on this page.
Stays via Stay22
Stays near Spearhead Lake
Compare lakeside cabins, hotels, and vacation rentals near Spearhead Lake in Skagit County, Washington — 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.
Top-rated places to stay near Spearhead Lake
Prices for Oct 30–Nov 1, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Washington’s top lakes →
Follow Spearhead Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Spearhead Lake
Nearby Lakes in Skagit County
Frequently asked questions about Spearhead Lake
Where is Spearhead Lake?
- Spearhead Lake is a lake in Skagit County, Washington. Its water-quality measurements are published by Washington Ecology and shown on this page as reported.
What is the water quality of Spearhead Lake?
- Spearhead Lake in Skagit County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Water clarity: 10.8 ft visibility. Phosphorus: 14 µg/L.
Is Spearhead Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Spearhead Lake across LakeQuality
16.4 mi away · 120 ft
21.2 mi away · recorded at 99°F
Species activity outlook by water temperature and season
Where to stay at Washington's top lakes, each with its readings
Washington's cleanest lakes, ranked on agency measurements
More lakes in Washington
Other Lakes in Washington
Mesotrophic Lakes in Washington
Where this data comes from
9 measurements from 2 monitoring stations, 2017. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Sauk-Suiattle Indian Tribe (Tribal)
SAUKSUIATTLE9 samples · 2017
Analytical methods
- 4500 P F ~ Phosphorus in Water by Colorimetry Automated Ascorbic Acid Method
Monitoring station identifiers (2)
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.