Link to the water quality test report

Crown beach is tested for bacterial levels weekly from April to October and twice a month from November to March. This map shows the sample sites which are: Crab Cove, the Bath House, Windsurf Corner, Sunset Road, 2001 Shoreline Drive, and Bird Sanctuary/Park Street. The East Bay Regional Park District works with the Alameda County Environmental Health Department in accordance with California Department of Public Health's Guidance for Salt Water Beaches to determine water quality at Crown Beach. Stop light signs along the beach are used to display the relative water quality from our latest bacteriological tests.
Water Quality Stop Light Designations:
Please be advised there is always some level of risk when swimming in any water body. 
To have a fun and safe experience swimming in the parks, we encourage you to follow a few simple rules:
* Keep bay water out of your mouth
* After you leave the water, shower and towel dry as soon as possible 
* Do not swim in the bay for 3 days after a rainstorm
* Check posted signs for water quality information