Beach Advisories (Postings and Closures) and Beach Water Quality Monitoring

One of California's biggest industries is tourism, and beaches are a significant tourist attraction as well as being an integral part of California’s culture and economy. Beaches, or more precisely the ocean waters adjacent to the beach, must be safe for swimming and other recreational use. When certain bacteria are present in sufficient concentrations, they pose a health hazard for swimming. County health officers issue various types of warnings when certain kinds of bacteria are found in the water at levels that exceed standards set by the Department of Health Services (DHS). These indicator bacteria imply the potential presence of microscopic disease-causing organisms originating from human and animal wastes. Not only does beach contamination pose real health risks to beach goers, the negative publicity that comes with postings and closures undermines the tourism industry. In California there are four types of warnings about beach water conditions: postings, closures, rain advisories, and permanent postings. Postings are the most common type of warning. Postings are triggered when a water sample fails to meet the DHS’ Ocean Water-Contact Sports Standard (California Health and Safety Code Sections 115875-115915). A beach posting is a warning to the public that the bacteria levels in the beach water may cause illness, and local health officers are recommending to the public to stay out of the water in areas where the signs are visible. The most common cause of postings is the dry weather discharge of urban runoff from storm drain systems. A beach closure is a notice to the public that there has been a sewage discharge that is affecting the beach area. Closures are put in place immediately after a sewage spill is reported that may affect the beach. The closed beach area will be reopened when water samples meet standards. Because closures represent a definite health risk and postings indicate a potential risk, they are tracked separately. Rain advisories are pre-emptive warnings that people should avoid swimming in ocean waters during a rain event and for three days after rainfall ceases. Rainwater often carries large amounts of bacteria from a variety of sources to the ocean. Rain advisories are issued via county hotlines, newspapers, and radio. Permanent postings are sites where urban runoff discharges to the beach even during the dry season, and historic data shows that the beach water near the discharge point generally contains elevated bacteria levels. The Water Board displays the closure and posting data submitted from the County Health Officers on its web site monthly. The Water Board also compiles the information into an annual report. These reports, available on the Water Board’s web site at https://www.waterboards.ca.gov/water_issues/programs/beaches/beach_surveys/, provide additional data on sources of pollution, testing methods, and causes of beach posting and closures.

Data files

Data title and descriptionAccess dataFile detailsLast updated

Beach Posting and Closures- Advisories

In California there are four types of warnings about beach water conditions: postings, closures, rain advisories, and permanent postings. Postings are the most common type of warning. Postings are triggered when a water sample fails to meet the DHS’ Ocean Water-Contact Sports Standard (California Health and Safety Code Sections 115875-115915). A beach posting is a warning to the public that the bacteria levels in the beach water may cause illness, and local health officers are recommending to the public to stay out of the water in areas where the signs are visible. The most common cause of postings is the dry weather discharge of urban runoff from storm drain systems. A beach closure is a notice to the public that there has been a sewage discharge that is affecting the beach area. Closures are put in place immediately after a sewage spill is reported that may affect the beach. The closed beach area will be reopened when water samples meet standards. Because closures represent a definite health risk and postings indicate a potential risk, they are tracked separately. Rain advisories are pre-emptive warnings that people should avoid swimming in ocean waters during a rain event and for three days after rainfall ceases. Rainwater often carries large amounts of bacteria from a variety of sources to the ocean. Rain advisories are issued via county hotlines, newspapers, and radio. Permanent postings are sites where urban runoff discharges to the beach even during the dry season, and historic data shows that the beach water near the discharge point generally contains elevated bacteria levels. The Water Board displays the closure and posting data submitted from the County Health Officers on its web site monthly. The Water Board also compiles the information into an annual report. These reports, available on the Water Board’s web site at https://www.waterboards.ca.gov/water_issues/programs/beaches/beach_surveys/, provide additional data on sources of pollution, testing methods, and causes of beach posting and closures.


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CSV
28.55 MB
10/30/25

Beach Water Quality Monitoring Stations

This dataset includes the details for the water quality monitoring stations associated with the beach water quality monitoring program. data elements include the location (latitude and longitude), the beach name and the county and agency doing the monitoring.


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CSV
631.92 KB
10/30/25

Beach Detail Information

The dataset includes the specific information associated with the California beaches. It includes the USEPA unique beach identifier, the county and the Regional Water Quality Control Board and the regulatory agency associated with each beach.


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CSV
149.09 KB
10/30/25

Beach Water Quality Monitoring Results - Bacteria

This dataset includes the beaches water quality monitoring results of the ocean waters adjacent to the beach. It includes bacteria monitoring results. County health officers issue various types of warnings when certain kinds of bacteria are found in the water at levels that exceed standards set by the Department of Health Services (DHS). These indicator bacteria imply the potential presence of microscopic disease-causing organisms originating from human and animal wastes. Not only does beach contamination pose real health risks to beach goers, the negative publicity that comes with postings and closures undermines the tourism industry.


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CSV
1.62 GB
10/30/25

Beach EPA Spatial data

Source: http://watersgeo.epa.gov/GEOSPATIALDOWNLOADS/rad_beach_20160715_shp.zip NOTE - the link is accessible from this page: https://www.epa.gov/waterdata/waters-geospatial-data-downloads#Beaches The data was filtered to only include data for California. Use the SRC_FEATID field in this spatial dataset to the USEPAID field in the "Beach information dataset"


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ZIP
158.70 KB
11/20/25

Supporting files

Data title and descriptionAccess dataFile detailsLast updated

Beach Watch Data Dictionary

Please use the following definitions for the data elements of the 4 Beach Watch datasets available in this platform.


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PDF
80.29 KB
11/20/25

WATERS Geospatial Data Downloads

Link to beach spatial data provided by USEPA including additional beach attributes


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11/20/25