Glenhaven Lake
Glenhaven Lake in Lake County, California has a water quality grade of A (Excellent). Chlorophyll-a (algae): 5.7 µg/L.
- Type
- Mesotrophic
Glenhaven Lake is a mesotrophic lake in Lake County, California. Water quality is graded A based on 1 sampling years through 2026. Compared to the 35 other monitored lakes in Lake County, Glenhaven Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2026-06-24. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
No clarity data. Chlorophyll-a: 5.7 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 5.7 µg/L | Good |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Glenhaven Lake
Compare lakeside cabins, hotels, and vacation rentals near Glenhaven Lake in Lake 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 Glenhaven Lake
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Fishing Glenhaven Lake
County Ranking
Ranked #2 of 36 lakes in Lake County
Nearby Lakes in Lake County
Frequently asked questions about Glenhaven Lake
Where is Glenhaven Lake?
- Glenhaven Lake is a lake in Lake County, California. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Glenhaven Lake?
- Glenhaven Lake in Lake County, California has a water quality grade of A (Excellent). Chlorophyll-a (algae): 5.7 µg/L.
Is Glenhaven Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Glenhaven Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 5.7 µg/L. Always check local health department advisories before swimming.
Explore Glenhaven Lake across LakeGrade
More California Lake Rankings
Other Grade A Lakes in California
Mesotrophic Lakes in California
Where this data comes from
62 measurements from 1 monitoring station, 2022–2026. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- Big Valley Band of Pomo Indians of the Big Valley Rancheria, California (Tribal)
CA_BVR62 samples · 2022–2026
Analytical methods
- Chlorophyll a
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.