Ninety days of readings.
Log scale · MPN/100mLEach dot is one sample taken by the monitoring agency. The dashed brick line marks the EPA single-sample limit.
SafeCautionUnsafe
A newer sample on Mar 12 (7 days ago) reported a different analyte, so the chart's last point is older than the most recent reading. The current reading shown above reflects that newer sample.
Common questions.
- Is Berkeley Aquatic Park — South Lagoon safe to swim today?
- Berkeley Aquatic Park — South Lagoon is currently inconclusive for swimming. Last sample is over 30 days old — too stale to be a reliable swim-safety indicator.
- When was Berkeley Aquatic Park — South Lagoon last tested?
- The most recent water-quality sample at Berkeley Aquatic Park — South Lagoon was collected on Mar 12, 2026 (82 days ago). California monitoring agencies test Bay Area beaches weekly during swim season (roughly May through October).
- Does rain affect water quality at Berkeley Aquatic Park — South Lagoon?
- 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 Berkeley Aquatic Park — South Lagoon located?
- Berkeley Aquatic Park — South Lagoon is located in the East Bay area of the San Francisco Bay region (coordinates: 37.8497°N, 122.2974°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 Berkeley Aquatic Park — South Lagoon 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.
Also nearby
Data: City of Berkeley — Aquatic Park Water Quality (Public Domain) · Open-Meteo — Precipitation (CC-BY 4.0) · Pipeline status