Where is Upper San Leandro Reservoir?

Upper San Leandro Reservoir is a lake in Alameda County, California. Its water-quality measurements are published by SWRCB and shown on this page as reported.

Upper San Leandro Reservoir

Alameda County, California705 acresView map Directions

SWRCB publishes the water-quality measurements for Upper San Leandro Reservoir. Here is what has been measured.

Chlorophyll-a

17.6 µg/L

Typical for California

Measured by SWRCB

Area

705 acres

Surface area

Shoreline

24.5 mi

Measured length

Impaired · Mercury
Limited data

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Upper San Leandro Reservoir in Alameda County, California has water-quality measurements published by SWRCB, shown here as reported. Chlorophyll-a (algae): 17.6 µg/L. Surface area: 705 acres.

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Upper San Leandro Reservoir is a 705-acre lake in Alameda County, California.

Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2017-06-13. Methodology: how these readings are compared.

Swimming conditions

No reading

Limited data

Nutrient and algae readings are not a swimming clearance. Upper San Leandro Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.

Whether Upper San Leandro Reservoir 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.

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Water quality measurements for Upper San Leandro Reservoir

These are the measurements SWRCB publishes for Upper San Leandro Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.

No clarity data. Chlorophyll-a 17.6 µg/L.

Water quality readings
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		No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential.
Chlorophyll-a (algae)	17.6µg/L	Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water.

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Lake Details

Surface area

705 acres

Shoreline

24.5 mi

No bathymetric survey has been published for Upper San Leandro Reservoir, so its depth is not documented here.

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Stays near Upper San Leandro Reservoir

Compare lakeside cabins, hotels, and vacation rentals near Upper San Leandro Reservoir in Alameda 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.

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Fishing Upper San Leandro Reservoir

→ Upper San Leandro Reservoir fishing regulations (limits, seasons, special rules)

EPA Impairment Status

Upper San Leandro Reservoir is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Mercury

Designated uses not supporting: Fish consumption, Other.

Source: EPA ATTAINS assessment unit CAL2042001120091208102529 · Official waterbody report

Nearby Lakes in Alameda County

Lake Chabot5.3 ft clear4.3 miView →Don Castro Reservoir0.3 ft clear7.4 miView →Lake Temescal6.2 ft clear7.7 miView →Lake Merritt5.2 ft clear8 miView →Jordan Pond2.5 ft clear—View →Horseshoe Lake12.7 ft clear—View →

Frequently asked questions about Upper San Leandro Reservoir

Where is Upper San Leandro Reservoir?: Upper San Leandro Reservoir is a lake in Alameda County, California. Its water-quality measurements are published by SWRCB and shown on this page as reported.
What is the water quality of Upper San Leandro Reservoir?: Upper San Leandro Reservoir in Alameda County, California has water-quality measurements published by SWRCB, shown here as reported. Chlorophyll-a (algae): 17.6 µg/L. Surface area: 705 acres.
Is Upper San Leandro Reservoir safe to swim in?: Nutrient and algae readings are not a swimming clearance. Upper San Leandro Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.