Working with the San Francisco Department of Public Health (SFDPH), we jointly administer the beach water quality monitoring program in San Francisco. Both agencies participate in sample collection; the San Francisco Water, Power and Sewer Microbiology Laboratory performs bacteriological analyses. San Francisco Water, Power and Sewer is responsible for public notification when water quality does not meet State standards for water contact recreation, while the SFDPH is responsible for ensuring compliance with the California Sanitation, Healthfulness and Safety of Ocean Water-Contact Sports Areas Regulations, Title 17, California Code of Regulations.
San Francisco’s Combined Sewer System (CSS) is unique in coastal California. In addition to normal sanitary, commercial, and industrial wastewater flows treated by separate sewer systems, a CSS collects and treats storm water. This offers significant environmental benefit because both storm water and urban street runoff are captured and treated. All street runoff during dry weather receives full secondary treatment, most storm flows receive full secondary treatment, and all storm flow receives treatment to at least wet-weather primary effluent equivalence before being discharged through a designated outfall. During heavy rain events, treated effluent typically comprised of 94% treated stormwater and 6% treated sanitary flow can discharge into coastal waters through the CSS. A system of underground storage, transport, and treatment boxes handles major rain events, minimizing the number of combined sewer system discharges. Best management practices are implemented to maximize storage and treatment and minimize shoreline discharges.
- 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 within 18 to 24 hours of sample collection. The units of measurement are Most Probable Number (of bacteria organisms) per 100 milliters of sample (MPN/100 mL).
- Results for samples collected one day are not available until the next day 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.
- Elevated bacteria counts most commonly occur in wet weather. The causes of elevated counts are not always clear, but are probably related to storm runoff from the beaches themselves that might contain human and animal feces, decaying plant and animal material, and naturally occurring soil bacteria.
- 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.
- Bacteria counts during dry weather are, with few exceptions, consistently low. Elevated counts during dry weather often have no readily apparent cause; however there is some indication that elevated counts might follow extreme high tide cycles.
- Yellow information signs are permanently posted along City beaches informing users that “No Swimming” signs will be posted when water quality does not meet California standards for water contact recreation and to call the San Francisco Water, Power and Sewer Recreational Water Quality Hotline or the SFDPH for more information.
- “No Swimming” signs are posted at major access points along recreational beaches when State recreational water contact standards are exceeded or whenever a Combined Sewer System discharge occurs that affects a recreational beach.
- E-mail notifications of beach postings and de-postings are sent to interested governmental and non-governmental organizations.
- The current status of beach water quality in San Francisco is available on the Recreational Beach Water Quality Hotline 415-242-2214 or 1-877-SFBEACH (toll-free). The hotline is updated whenever new sample results are available (twice weekly at a minimum). The information provided includes the date and results (posted/not posted) of the most recent samples and additional information related to combined sewer system discharges, rain advisories, etc., as warranted.
- The current status of beach water quality in San Francisco is also available on the internet at http://beaches.sfwater.org/. The site uses color-coded symbols on a map of the City to provide an at-a-glance view of water quality status. Additional information including monitoring program description, monitoring station locations, beach descriptions and photos, and recent sample results are available by clicking on the station symbols.
Beach Posting Due to Treated Combined Sewer System (CSS) Discharges
Whenever a treated CSS discharge occurs that affects Ocean Beach (including Fort Funston), China Beach, Baker Beach, or Candlestick Point State Recreation Area:
- Affected beaches are posted with “No Swimming” signs and samples are collected as soon as practical after a discharge occurs.
- Beaches remain posted and samples are collected daily until the discharge ceases and all three bacteria indicators (total coliform, Escherichia coli, and enterococcus) are below State levels for water contact recreation.
- Public notifications are provided through the Water Quality Hotline, e-mail, and the internet. The web site http://beaches.sfwater.org/ is flagged with a flashing symbol to indicate the discharge location(s). The flashing symbol remains active until the discharge has ceased and all affected sample locations are below California standards for water contact recreation. If elevated bacteria levels persist more than three days after the last discharge, the flashing symbol is removed and the station(s) remain(s) posted.
Information about Combined Sewer System Discharges:
- San Francisco’s combined sewer system (CSS) is different from other coastal cities in California and offers significant environmental benefit because it captures and treats both storm water and urban street runoff in addition to commercial, industrial and sanitary wastewater.
- All street runoff during dry weather receives full secondary treatment, most storm flows receive full secondary treatment, and all storm flow receives treatment to at least wet-weather primary effluent equivalence before being discharged through a designated outfall. CSS discharges do not contain raw, untreated sewage.
- During heavy rain events, the CSS can discharge into coastal waters a combined effluent typically comprised of 94% treated stormwater and 6% treated sanitary flow. A system of underground storage, transport, and treatment boxes handles major rain events, minimizing the number of combined sewer system discharges.
- Another advantage of the CSS is that discharges onto beaches are of much shorter duration and smaller volume than those that might occur in communities with separate storm drains and sanitary sewers.
- There are no CSS discharge points within close proximity to Crissy Field Beach or Aquatic Park.
Beach Posting Due to Elevated Bacteria Counts
The causes of elevated bacteria counts not associated with CSS 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. There is some indication that elevated counts might follow extreme high tides.
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 Rationale for Confirmation before Posting, below). 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.
- Stations not requiring confirmation to post: Baker Beach at Lobos Creek (station 15), Crissy Field Beach (stations 202.4, 202.5), and Candlestick Point State Recreation Area at Windsurfer Circle (station 301.2).
Stations in this category are posted with “No Swimming” signs when one or more of the bacteria indicators are above the California standards for water contact recreation:
- Total Coliform > 10,000 MPN/100 mL
- Escherichia coli > 400 MPN/100 mL (a surrogate for fecal coliform)
- Enterococcus > 104 MPN/100mL
Stations remain posted and are re-sampled daily until all three indicators fall below State standards for water contact recreation.
Stations requiring confirmation to post: Ocean Beach (stations 18 and 19 are linked, station 21.1), China Beach (station 17), Baker Beach (stations 15E and 16 are each independently linked to station 15), Aquatic Park (stations 210.1 and 211 are linked), and Candlestick Point State Recreation Area (stations 300.1 and 301.1 are linked, station 301.2).
Stations in this category are only posted with “No Swimming” signs when one or more of the following confirmation criteria are met:
More than one indicator exceeds its respective single sample maximum at a single station.
One or more indicator exceeds its respective single sample maximum at a linked station on the same date.
One or more indicator exceeds its respective single sample maximum in a repeat sample.
If a single indicator exceeds State standards and confirmation criterion 1) or criterion 2) is not met, the station is re-sampled and evaluated using criterion 3). Once posted, stations remain posted and are re-sampled daily until all three indicators fall below State standards for water contact recreation.
Rationale for Confirmation before Posting
The Beach Water Quality Workgroup of the California State Water Resources Control Board charged its Monitoring and Reporting Subcommittee with: 1) evaluating the existing monitoring program mandated by State law (AB 411), 2) reviewing the latest scientific findings regarding effectiveness and reliability of that program, and 3) recommending changes to increase public health protection and public notification for those engaged in ocean water contact activities.
Although the beach water quality monitoring program conducted in San Francisco by San Francisco Water, Power and Sewer and SFDPH is not regulated by AB411, implementing the recommendations of the Monitoring and Reporting (M&R) Subcommittee provides optimal information delivery to the public and will also assure that San Francisco’s program is consistent with other programs throughout the State, to the extent practical. The Guidance Document prepared by the M&R Subcommittee and adopted by the Beach Water Quality Workgroup recognizes three types of beaches, each with distinct water quality issues:
Open Coastal Beaches with tidal flushing and unimpeded swell energy, with no known sources of contamination affecting water quality and a history of good water quality.
The M&R Subcommittee recommends employing a confirmation approach to posting this type of beach when a single sample standard is exceeded. Routine beach monitoring data have shown that many recreational beaches in San Francisco have a history of good water quality, with no known source of contamination, and with sufficient circulation that the confirmation approach is appropriate. Specific exceptions are indicated below. In contrast to routine monitoring, Combined Sewer System discharges at these beaches are discrete events that require a separate response not involving confirmation.
Beaches with storm drain, creek, or river discharges during the summer.
The M&R Subcommittee recommends permanent posting for beaches within this category. In San Francisco, Baker Beach at Lobos Creek and storm drains at two areas outside of the combined sewer system (Crissy Field Beach and Windsurfer Circle within the Candlestick Point State Recreation Area), represent known or potential sources of dry weather contamination. Confirmation is not required at these sites. Permanent information signs are posted at these locations.
Beaches in an enclosed harbor, bay, or estuary.
The M&R Subcommittee recommends an approach requiring “best professional judgment” for these beaches. In San Francisco, Aquatic Park qualifies as an enclosed body of water. Monitoring data indicate that a confirmation approach is appropriate at Aquatic Park.
Confirmation: For stations that, during routine monitoring require confirmation before being posted, confirmation is provided when one or more of the following occur:
More than one indicator exceeds their respective single sample maximum at a single station.
One or more indicators exceed their respective single sample maximum at linked stations.
One or more indicators exceed their respective single sample maximum in a repeat sample.
Linked Stations: Stations that are hydrologically connected such that, during routine monitoring, single indicator exceedences at both stations provide the necessary confirmation for posting.