San Gregorio State Beach (Peninsula, North)

Each dot is one sample taken by the monitoring agency. Dashed lines mark each indicator's EPA single-sample limit; bars along the bottom show daily rainfall.

Common questions.

Is San Gregorio State Beach (Peninsula, North) safe to swim today?

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San Gregorio State Beach (Peninsula, North) is currently safe for swimming. Recent samples within safe ranges.

When was San Gregorio State Beach (Peninsula, North) last tested?

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The most recent water-quality sample at San Gregorio State Beach (Peninsula, North) was collected on Sep 14, 2026 (8 days ago). California monitoring agencies test Bay Area beaches weekly during swim season (roughly May through October).

What is the bacteria level at San Gregorio State Beach (Peninsula, North)?

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The latest reading at San Gregorio State Beach (Peninsula, North) shows 30-day enterococcus geomean at 17 MPN/100mL (EPA geomean limit: 35); enterococcus at 10 MPN/100mL (EPA single-sample limit: 104); and E. coli at 10 MPN/100mL (EPA single-sample limit: 235).

Does rain affect water quality at San Gregorio State Beach (Peninsula, North)?

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Yes. Heavy rainfall washes bacteria and pollutants from land into the water, raising contamination risk for 24–72 hours. The past 48 hours recorded 0.00 in of rain; the past 72 hours recorded 0.00 in. Our advisory threshold is ≥1.00 in over 48h (or ≥0.50 in over 72h) for enclosed or storm-drain beaches.

Where is San Gregorio State Beach (Peninsula, North) located?

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San Gregorio State Beach (Peninsula, North) is located in the Peninsula area of the San Francisco Bay region (coordinates: 37.3224°N, 122.4040°W). You can get turn-by-turn directions via Google Maps or Apple Maps directly from this page.

How is the water quality data for San Gregorio State Beach (Peninsula, North) collected?

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Bacteria samples are collected by California state and county health agencies under the AB 411 Safe-to-Swim program and reported to the state's Safe-to-Swim database (data.ca.gov). Rainfall figures come from Open-Meteo forecast and archive data. Bay Area Swim aggregates both sources and updates every morning.