California: water quality is generally good | Photo: Parker Knight/Creative Commons

The 25th annual Beach Report Card reveals that Cowell Beach, at the wharf in Santa Cruz County, is considered the worst spot and the most polluted beach of the 2014/2015 season.

According to Heal the Bay, only 13 of the beaches monitored statewide received D to F grades during summer dry weather, when most beachgoers typically use the ocean.

High bacteria counts at these sites are linked to potential illnesses like stomach flu, ear and upper respiratory infections and major skin rashes.

Bay Area ocean beaches continue to provide outstanding water quality for summer beachgoers, but swimmers faced worrying pockets of pollution in San Mateo and San Francisco counties.

The severe drought now impacting California is a major contributing factor to improved water quality at beaches statewide. With record low rainfall reducing the amount of polluted runoff funneled into our seas, scores rose on a year-to-year basis across the state.

"It's encouraging that the Bay Area's water quality has continued to improve during the peak summer season. However, this past year's record dry conditions have likely had a strong influence on this year's improved beach water quality grades," James Alamillo, scientist and lead author of the report.

Heal the Bay's annual Beach Bummer List, a ranking of the state's 10 most polluted beaches, is evenly split among beaches in Southern and Northern California.

Fortunately, there are 19 Californian beaches with excellent water quality all year. They were monitored year-round and scored perfect A+ grades every week of the year, regardless of dry or rainy conditions.

2015 Beach Bummers

1. Cowell Beach - at the wharf (Santa Cruz County)
2. Marina del Rey - Mother's Beach (Los Angeles County)
3. Clam Beach County Park (Humboldt County)
4. Marina Lagoon (San Mateo County)
5. Mission Bay at Clairmont Drive (San Diego County)
6. Stillwater Cove (Monterey County)
7. Candlestick Point/Sunnydale Cove (San Francisco County)
8. Santa Monica Pier (Los Angeles County)
9. Cabrillo Beach harborside (Los Angeles County
10. Huntington State Beach at Brookhurst (Orange County)

2014-2015 Honor Roll

San Luis Obispo County
San Simeon, at Pico Avenue
Morro Bay City Beach,
projection of Atascadero

Santa Barbara County
El Capitan State Beach

Ventura County
Oil Pier Beach, south of drain
Solimar Beach, south
Surfer’s Point at Seaside
Surfer’s Knoll

Los Angeles County
Bluff Cove, Palos Verdes Estates
Abalone Cove Shoreline Park
Portuguese Bend Cove,
Rancho Palos Verdes

Orange County
Balboa Beach, The Wedge
Treasure Island Beach
Laguna Lido Apartments
Dana Point Harbor Guest Dock

San Diego County
Encinitas, San Elijo State Park
Cardiff State Beach,
Charthouse parking
Ocean Beach, Ocean Pier
Point Loma, Lighthouse
Coronado, Silver Strand