San Mateo County Lake Quality

San Mateo County holds 7 monitored lakes. With a sample that small the county-level summary describes those specific waters, not necessarily every water body in the county. The 7 monitored lakes in San Mateo 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.