Drakes Estero

Each dot is one sample taken by the monitoring agency. The dashed brick line marks the EPA single-sample limit.

Common questions.

Is Drakes Estero safe to swim today?

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Drakes Estero is currently safe for swimming. Recent samples within safe ranges.

When was Drakes Estero last tested?

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The most recent water-quality sample at Drakes Estero was collected on May 18, 2026 (15 days ago). California monitoring agencies test Bay Area beaches weekly during swim season (roughly May through October).

What is the bacteria level at Drakes Estero?

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The latest reading at Drakes Estero shows 30-day enterococcus geomean at 16 MPN/100mL (EPA geomean limit: 35); enterococcus at 10 MPN/100mL (EPA single-sample limit: 104); and E. coli at 20 MPN/100mL (EPA single-sample limit: 235).

Does rain affect water quality at Drakes Estero?

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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 Drakes Estero located?

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Drakes Estero is located in the Marin area of the San Francisco Bay region (coordinates: 38.0828°N, 122.9330°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 Drakes Estero 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.