Rodeo Lagoon W Top Lake
Rodeo Lagoon W Top Lake in Marin County, California is not rated for water quality — its monitoring record does not meet the evidence bar. Chlorophyll-a (algae): 66.7 µg/L.
Why Rodeo Lagoon W Top Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: 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 Rodeo Lagoon W Top Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded algae (chlorophyll-a), but not water clarity and phosphorus.
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 your state environmental agency and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Rodeo Lagoon W Top Lake is a lake in Marin County, California.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2022-08-03. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Rodeo Lagoon W Top Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
No clarity data. Chlorophyll-a: 66.7 µg/L. Trophic State Index: 72.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 66.7 µg/L | Not graded |
| Trophic State Index (TSI) | 72 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Rodeo Lagoon W Top Lake
Compare lakeside cabins, hotels, and vacation rentals near Rodeo Lagoon W Top Lake in Marin County, California — 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 Rodeo Lagoon W Top Lake
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Fishing Rodeo Lagoon W Top Lake
Graded lakes near Rodeo Lagoon W Top Lake
Rodeo Lagoon W Top Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Marin County
Frequently asked questions about Rodeo Lagoon W Top Lake
Where is Rodeo Lagoon W Top Lake?
- Rodeo Lagoon W Top Lake is a lake in Marin County, California. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Rodeo Lagoon W Top Lake?
- Rodeo Lagoon W Top Lake in Marin County, California is not rated for water quality — its monitoring record does not meet the evidence bar. Chlorophyll-a (algae): 66.7 µg/L.
Is Rodeo Lagoon W Top Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Rodeo Lagoon W Top Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Algae concentration (chlorophyll-a) is 66.7 µg/L. Always check local health department advisories before swimming.
Explore Rodeo Lagoon W Top Lake across LakeGrade
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Hypereutrophic Lakes in California
Where this data comes from
1 measurement from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- USGS California Water Science Center
USGS-CA1 sample · 2022
Analytical methods
- Plant pigments, sonication & 445
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.