Water quality at California beaches should always be a concern if you plan to enter the water. Swimmers and surfers should be informed before heading to the beach anywhere along the shoreline. Bays, harbors, and marinas, where the water gets less flushing to clear out contaminates, can be the most dangerous. This is definitely true after a heavy rain because street runoff contains all sorts of chemicals and bacteria that wind up in these bodies of water. During hot spells, the water in bays can warm up significantly and add to the stagnation that poisons the water. Ocean beaches are typically safer but not always safe, especially after storms and near creek mouths and storm drain outlet pipes. Always check water quality reports before you head to the beach.
The leading authority on water quality on the West Coast is the non-profit Heal The Bay. They produce an annual report that gives a picture of which beaches are improving and which are getting worse. This has put pressure on leaders in these coastal communities to do something about poor water quality. HTB has nearly 500 different water testing locations along the California coast, but there are still gaps with areas that are not tested. Their county maps are useful for locating the nearest water test and seeing the current grade (A+ is best and F is worst).
We have organized their pages into the links below to make it easy to find this data. These areas are listed south to north.
San Diego County – including San Diego, San Diego Bay, Mission Bay, Coronado, Imperial Beach, La Jolla, Del Mar, Solana Beach, Encinitas, Carlsbad, and Oceanside
Orange County – including Laguna Beach, Newport Beach, Corona Del Mar, Huntington Beach, Dana Point, San Clemente, and Seal Beach
Los Angeles County – including Los Angeles, Long Beach, San Pedro, Palos Verdes, Torrance, Redondo, Manhattan Beach, Marina Del Rey, Venice, Santa Monica, and Malibu
Catalina Island – just the beaches around Avalon
Ventura County – including Ventura, Oxnard, Port Hueneme, Faria Beach, Mussel Shoals, and La Conchita
Santa Barbara County – including Santa Barbara, Carpinteria, Summerland, Goleta, Isla Vista, Gaviota, Lompoc, and Guadalupe
San Luis Obispo County – including Pismo Beach, Avila Beach, Morro Bay, Cayucos, Cambria, San Simeon, and Oceano.
Monterey County – including Monterey, Carmel, Pacific Grove, Pebble Beach, Big Sur, Seaside, Marina, and Moss Landing
Santa Cruz County – including Santa Cruz, Capitola, Aptos, Rio Del Mar, La Selva Beach, Watsonville, and Davenport
San Mateo County – including Daly City, Pacifica, Half Moon Bay, Princeton, Montara, Moss Beach, Pescadero, San Gregorio, and San Mateo & South San Francisco on the Bay
San Francisco – including the ocean beaches and bay beaches in the city of San Francisco
Alameda County – including Oakland and Alameda areas on San Francisco Bay
Contra Costa County – including the Richmond area on San Francisco Bay
Marin County – including Point Reyes, Sausalito, Tiburon, San Rafael, Muir Beach, Stinson Beach, Bolinas, Inverness, and Dillon Beach
Sonoma County – including Bodega Bay, Jenner, Timber Cove, and Sea Ranch
Mendocino County – including Fort Bragg, Mendocino, Little River, and Caspar
Humboldt County – including Eureka, Arcata, McKinleyville, and Trinidad
Del Norte County – including Crescent City and the Klamath area