Castle Lake
Castle Lake in Cowlitz County, Washington is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 279 acres.
- Area
- 279 acres
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Why Castle Lake has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Castle Lake, no water-quality sampling on record for this lake.
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by WA Ecology and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Castle Lake is a 279-acre lake in Cowlitz County, Washington.
Source: EPA Water Quality Portal sampling records, WA Ecology, last sampled recent years. Grade methodology: LakeQuality methodology.
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Swimming Safety
Not ratedElevated nutrients
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Castle Lake
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Trophic State Index: undefined.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) |
Where to stay near Castle Lake
Compare lakeside cabins, hotels, and vacation rentals near Castle Lake in Cowlitz 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 Castle Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 279 acres |
No bathymetric survey has been published for Castle Lake, so its depth is not documented here.
Fishing Castle Lake
Nearby Lakes in Cowlitz County
Frequently asked questions about Castle Lake
Where is Castle Lake?
- Castle Lake is a lake in Cowlitz County, Washington. LakeQuality has not rated this lake (UNRATED) — no water-quality sampling on record for this lake.
What is the water quality grade for Castle Lake?
- Castle Lake in Cowlitz County, Washington is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 279 acres.
Is Castle Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Castle Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
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Where this data comes from
Measurements for Castle Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.