La Posta Lake Surface
San Diego County, CaliforniaView mapDirections
SWRCB publishes the water-quality measurements for La Posta Lake Surface. Here is what has been measured.
- Limited data
La Posta Lake Surface in San Diego County, California has water-quality measurements published by SWRCB, shown here as reported. Phosphorus: 80 µg/L.
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. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether La Posta Lake Surface is safe to swim in today is a call for the California State Water Resources Control Board and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for La Posta Lake Surface
These are the measurements SWRCB publishes for La Posta Lake Surface, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 80 µg/L. TSI 67.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 80µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 67 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
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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. Its water-quality measurements are published by SWRCB and shown on this page as reported.
What is the water quality of La Posta Lake Surface?
- La Posta Lake Surface in San Diego County, California has water-quality measurements published by SWRCB, shown here as reported. Phosphorus: 80 µg/L.
Is La Posta Lake Surface safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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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)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.