La Posta Lake Surface
La Posta Lake Surface in San Diego County, California is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 80 µg/L.
Why La Posta Lake Surface 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 La Posta Lake Surface, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded phosphorus, but not water clarity and algae (chlorophyll-a).
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.
La Posta Lake Surface is a lake in San Diego County, California.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2022-09-15. 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 La Posta Lake Surface
These readings exist but do not meet the evidence bar for an A–F grade — see why.
No clarity data. Phosphorus level: 80 µg/L. Trophic State Index: 67.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 80 µg/L | Not graded |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 67 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near La Posta Lake Surface
Compare lakeside cabins, hotels, and vacation rentals near La Posta Lake Surface in San Diego 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 La Posta Lake Surface
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Fishing La Posta Lake Surface
Graded lakes near La Posta Lake Surface
La Posta Lake Surface has no grade, but these lakes within a short drive do.
Nearby Lakes in San Diego County
Frequently asked questions about La Posta Lake Surface
Where is La Posta Lake Surface?
- La Posta Lake Surface is a lake in San Diego 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 La Posta Lake Surface?
- La Posta Lake Surface in San Diego County, California is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 80 µg/L.
Is La Posta Lake Surface safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. La Posta Lake Surface is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Explore La Posta Lake Surface across LakeGrade
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Where this data comes from
14 measurements from 1 monitoring station, 2021–2022. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- La Posta EPA (Tribal)
LPEPA10614 samples · 2021–2022
Analytical methods
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 4500 P B ~ Phosphorus, sample preparation method
- TN Calculation
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.