Herman Impoundment Lake
Herman Impoundment Lake in Lake County, California is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 3 µg/L. Chlorophyll-a (algae): 1.5 µg/L.
Why Herman Impoundment 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 Herman Impoundment Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded phosphorus and algae (chlorophyll-a), but not water clarity.
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.
Herman Impoundment Lake is a lake in Lake County, California.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2023-05-02. 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 Herman Impoundment Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
No clarity data. Phosphorus level: 3 µg/L. Chlorophyll-a: 1.5 µg/L. Trophic State Index: 27.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 3 µg/L | Not graded |
| Chlorophyll-a (Algae) | 1.5 µg/L | Not graded |
| Trophic State Index (TSI) | 27 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Herman Impoundment Lake
Compare lakeside cabins, hotels, and vacation rentals near Herman Impoundment 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 Herman Impoundment Lake
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Fishing Herman Impoundment Lake
Graded lakes near Herman Impoundment Lake
Herman Impoundment Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Lake County
Frequently asked questions about Herman Impoundment Lake
Where is Herman Impoundment Lake?
- Herman Impoundment Lake is a lake in Lake 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 Herman Impoundment Lake?
- Herman Impoundment Lake in Lake County, California is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 3 µg/L. Chlorophyll-a (algae): 1.5 µg/L.
Is Herman Impoundment Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Herman Impoundment Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Algae concentration (chlorophyll-a) is 1.5 µg/L. Always check local health department advisories before swimming.
Explore Herman Impoundment Lake across LakeGrade
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Other Lakes in California
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Where this data comes from
6 measurements from 1 monitoring station, 2022–2023. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- USGS California Water Science Center
USGS-CA6 samples · 2022–2023
Analytical methods
- P, wu, WCA, persulfate CF color
- Plant pigments, sonication & 445
- YSI Environmental, sensor 6136
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.