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.
Each dot is one sample taken by the monitoring agency. The dashed brick line marks the EPA single-sample limit.
SafeCautionUnsafe
Common questions.
Is South Beach-Keller Beach (Contra Costa Co) safe to swim today?
+
South Beach-Keller Beach (Contra Costa Co) 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 South Beach-Keller Beach (Contra Costa Co) last tested?
+
The most recent water-quality sample at South Beach-Keller Beach (Contra Costa Co) was collected on Aug 10, 2026 (14 days ago). California monitoring agencies test Bay Area beaches weekly during swim season (roughly May through October).
What is the bacteria level at South Beach-Keller Beach (Contra Costa Co)?
+
The latest reading at South Beach-Keller Beach (Contra Costa Co) shows enterococcus at 120 MPN/100mL (EPA single-sample limit: 104); and 30-day enterococcus geomean at 23 MPN/100mL (EPA geomean limit: 35).
Does rain affect water quality at South Beach-Keller Beach (Contra Costa Co)?
+
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 South Beach-Keller Beach (Contra Costa Co) located?
+
South Beach-Keller Beach (Contra Costa Co) is located in the East Bay area of the San Francisco Bay region (coordinates: 37.9207°N, 122.3870°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 South Beach-Keller Beach (Contra Costa Co) collected?
+
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.