Residents and tourists enjoying the long holiday weekend have been advised that several San Diego County beaches have levels of bacteria in the water that exceed state standards. Despite the advisories at nine beaches, as well as a couple of closures, most of the county’s coastline remains unaffected.

The beach advisories span the 70-mile county coastline, even into North County. The advisories are issued for Mission Bay at Tecolote Shores, Campland Beachline and Santa Clara Cove, La Jolla at La Jolla Cove Beachline, Del Mar at San Dieguito River outlet, Encinitas at Cardiff State Beach, and San Elijo Lagoon outlet.

The county Department of Environmental Health and Quality issued the advisories due to bacteria levels in ocean or bay water samples exceeding public health standards, and revelers are asked to avoid contact with water in the advisory areas.

The advisories were imposed in late June and early July, though La Jolla Cove’s Children’s Pool, home to harbor seals and seal lions that lie out on the beach year-round, has been under an advisory since September 1997.

Ahead of the weekend, San Diego County beach advisories were rescinded for Los Peñasquitos Lagoon in Torrey Pines State Beach, Dog Beach in Ocean Beach, and the Silver Strand Shoreline in Coronado.

Beachgoers will be able to spot the yellow hazard signs near the entrances of beaches and on the sand.

Sewage pouring out of Mexico into the ocean and reaching up the San Diego County coastline has also long been a concern in the region.

The Tijuana Slough Shoreline, stretching from the border to the Tijuana Slough National Wildlife Refuge, is closed as a result of cross-border sewage flows. This part of San Diego’s coastline has been closed since December 2021.

The Imperial Beach Shoreline, from the south end of Seacoast Drive through Imperial Beach Pier, has been closed since January 2025.

The polluted Tijuana River also affects the air quality in many parts of San Diego, according to a study by UC San Diego. The pollutants found in both the water and air include octinoxate, which is used in some sunscreens and lip balms.

“It’s been shown that octinoxate can degrade DNA when exposed to light,” said Jonathan Slade, UC San Diego assistant professor of chemistry and biochemistry. “And if it’s in these tiny aerosols we’re breathing in, it can get deep into our lungs and pass into our bloodstream. That’s very concerning, especially considering the high levels at which we found it in the air.”

Water quality throughout most of the county—for instance, at the popular Tidelands Park on Coronado Island or La Jolla Shores—does not fall under any advisories or closures.

The weather outlook for San Diego County beaches calls for dry conditions, with highs in the 70s and water temperatures between 62 and 64 degrees. Morning clouds on the coast will clear out by the afternoon.

The National Weather Service warns of an elevated beach hazard with surf as high as six feet across San Diego and Orange County beaches.