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LakeQuality
Late afternoon sun over Slim Lake, scattering a bright path across wind-textured water

Contra Costa County Lake Quality

California, 16 lakes, measured by SWRCB

There are 16 monitored lakes in Contra Costa County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. The 16 monitored lakes in Contra Costa County carry whatever clarity, phosphorus, and chlorophyll-a readings SWRCB has published, shown as reported.

Most of the county's monitored lakes are shallow, under 50 feet, which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed.

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Where to stay near Contra Costa County

Top-rated places to stay near Contra Costa County

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Quick Answers for Contra Costa County

Cleanest lakes in Contra Costa County →Best swimming lakes in California →

Planning a trip? Check special fishing regulations for Antioch Municipal Reservoir — or check the official California fishing regulations.

All Lakes in Contra Costa County

16 lakes · 0 ranked on readings, 16 without enough sampling0 lakes ranked on readings · 16 without enough sampling, hidden

#LakeClarityPhosphorusAlgaeTrophicAccess
Antioch Municipal ReservoirContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Briones ReservoirContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Clifton Court ForebayContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Contra Loma ReservoirContra Costa4.1 ftNo recent samplesNo recent samplesNo recent samples✓ Public
Holland Tract Middle PondContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Holland Tract North PondContra CostaNo recent samplesNo recent samples103.5 µg/LNo recent samples✓ Public
Holland Tract South PondContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
Lafayette ReservoirContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
Lake AnzaContra Costa12.3 ftNo recent samplesNo recent samplesNo recent samplesNot recorded
Mallard ReservoirContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Marsh Creek ReservoirContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
San Pablo ReservoirContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Webb Tract East PondContra CostaNo recent samplesNo recent samples88.3 µg/LNo recent samplesNot recorded
Webb Tract Middle PondContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
Webb Tract North PondContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
Willow LakeContra CostaNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded

NR = no nutrient or algae reading on record. The measurements are published as the authority reports them. Where the data comes from.

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Other Counties in California

Plumas County

19 lakes

Amador County

12 lakes

Placer County

16 lakes

Butte County

16 lakes

Nevada County

35 lakes

Santa Clara County

13 lakes

Browse every California lake, or the full directory of lakes across all United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs..

Source: the California State Water Resources Control Board. See data sources.