RIVER GAUGE · SAN GREGORIO CREEK
San Gregorio Creek at San Gregorio
San Mateo County, California
Water level3.70 ft
Flow4 cfs
Last readingSep 16, 2026, 4:15 PM UTC (last recorded)
Action15 ft
Minor flood17.7 ft
Moderate flood21 ft
Major flood25 ft
The past week
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What floods at each level
- 25 ft
Major flood stage. Stage Road at San Gregorio Creek flooded and adjacent floodplain properties under 4 or more feet of water.
- 21 ft
Moderate flood stage. Adjacent floodplain under several feet of water. Stage Road crossing is backwatered.
- 17.7 ft
Minor flood stage. Flood waters inundate floodplain upstream of Stage Road crossing, mainly on left bank side (as looking downstream). NWS will issue a Flash Flood Warning if not yet already issued.
- 15 ft
Action Stage. Water is 2.7 feet below adjacent floodplain properties. NWS may issue a Flash Flood Watch if not yet already issued.
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