General Beach Monitoring Information
- Fourteen sites are monitored weekly at beaches around the perimeter of San Francisco where water contact recreation is common:
- Candlestick Point State Recreation Area (Sunnydale Cove, Windsurfer Circle, and Jackrabbit Beach)
- Aquatic Park (Hyde Street Pier and Aquatic Park Beach)
- Crissy Field (Crissy Field East and Crissy Field West)
- Baker Beach (Baker Beach East, Baker Beach at Lobos Creek, and Baker Beach West)
- China Beach
- Ocean Beach (at the foot of Balboa Street, at the foot of Lincoln Way, and the foot of Sloat Boulevard)
- Samples are analyzed for three different bacterial indicators of impaired water quality (total coliform, Escherichia coli, and enterococcus) by the quanti-tray method.
- Results are available the day after the samples are taken because it takes time to culture the bacteria in order to obtain an accurate estimate of their abundance. Beaches are posted and the public is notified 18 to 24 hours after an elevated concentration of bacteria occurs. This is done in case the elevated bacteria concentrations persist.
- In order to provide as rapid a response as possible the City proactively posts (and de-posts) beaches and makes public notifications based upon preliminary bacteria counts made available before final results are confirmed. The public is better served overall by timely notifications based upon preliminary counts than by the necessary delay needed to act upon confirmed counts.
- Beach users concerned with the potential for exposure to elevated bacteria concentrations are advised to avoid water contact recreation during and immediately after rain events.
What Causes Elevated Bacteria Counts?
The causes of elevated bacteria counts not associated with combined sewer discharges are not always clear; they may be related to storm runoff from the beaches themselves that might contain human or animal feces, decaying plant or animal material, or naturally occurring sand or soil bacteria.
Because elevated counts for a single indicator may be spurious and historical data indicate that such counts are typically not persistent, we have adopted a confirmation approach to posting beaches that lack sources of pollution. See the Rationale for Confirmation before Posting. For those beaches, confirmation is provided by a second elevated indicator in the same sample, an elevated indicator at a linked station (if applicable), or an elevated indicator in a repeat sample.
We post “No Swimming” signs at San Francisco beaches when water quality does not meet California standards for water contact recreation. We also post signs whenever a Combined Sewer System discharge occurs that affects a recreational beach.
The current status of San Francisco beach water quality is available on the Recreational Beach Water Quality Hotline 415-242-2214 or 1-877-SFBEACH (toll-free). The hotline and website are updated whenever new sample results are available.