Patagonia Lake is a productive, nutrient-rich eutrophic lake in Santa Cruz County, Arizona. Water quality is graded C based on 1 sampling years through 2026. Compared to the 1 other monitored lakes in Santa Cruz County, Patagonia Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Arizona DNR, last sampled 2026-04-06. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Good clarity, visible to about 11.2 ft. Phosphorus level: 58 µg/L. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 11.2 ft | B |
| Phosphorus | 58 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Patagonia Lake
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Fishing Patagonia Lake
Location
County Ranking
Ranked #1 of 2 lakes in Santa Cruz County
Cleaner Lakes Within 30 Miles
Patagonia Lake holds Grade C. One nearby lake has a higher grade.
Nearby Lakes in Santa Cruz County
Explore Patagonia Lake across LakeGrade
More Arizona Lake Rankings
Other Grade C Lakes in Arizona
Eutrophic Lakes in Arizona
More records, surveys & data sources
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2026-04-06
Monitoring stations: 1