Frenchmans Creek

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

Common questions.

Is Frenchmans Creek safe to swim today?

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Frenchmans Creek is currently not safe for swimming. One or more bacteria readings exceeded EPA thresholds in the most recent sample. See the readings below for which indicator and how far above the limit.

When was Frenchmans Creek last tested?

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The most recent water-quality sample at Frenchmans Creek was collected on May 26, 2026 (7 days ago). California monitoring agencies test Bay Area beaches weekly during swim season (roughly May through October).

What is the bacteria level at Frenchmans Creek?

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The latest reading at Frenchmans Creek shows E. coli at 1,354 MPN/100mL (EPA single-sample limit: 235).

Does rain affect water quality at Frenchmans Creek?

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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 Frenchmans Creek located?

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Frenchmans Creek is located in the Peninsula area of the San Francisco Bay region (coordinates: 37.4808°N, 122.4515°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 Frenchmans Creek 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.