This Fourth of July may not include the beach trip you were expecting. San Diego County’s Beach and Bay Program — which measures water quality along the county’s coast — is asking people to avoid the water in several locations.

Several coastal areas in Coronado, Mission Beach, Ocean Beach, La Jolla, Del Mar and Cardiff State Beach were under excessive bacteria advisories as of Monday night. Beachgoers can spot yellow signs at entrances.

  • Coronado: Silver Strand from north of Carnation to south of Avenida Lunar; Avenida Luna
  • Mission Bay: Tecolote Shores swim area
  • Ocean Beach: Dog beach
  • La Jolla: La Jolla Cove Beachline; Children’s Pool
  • Del Mar: San Dieguito River outlet
  • Cardiff State Beach: Charthouse parking lot; San Elijo Lagoon Outlet

Such advisories mean ocean or bay water quality does not meet state health standards due to high bacterial levels.

“We are beach people, so we want to be able to enjoy it,” beachgoer Domonique Estay-Foix said.

Estay-Foix and her family and beating the holiday crowds. She is less concerned about herself than her little ones.

“It is to be careful with the kids, especially because they are so little,” Estay-Foix said.

Cardiff State Beach is the northern-most beach destination under the advisory.

“I’m not going to put my head in the water right here by the pipe,” body surfer Ty Miller said.

Miller has been body surfing that beach for decades. The pipe is between Pacific Coast Grill and Chart House restaurants. It’s part of the dredging project dumping thousands of gallons of lagoon water and sediment into the ocean. It has the distinct scent of sulfur.

“I think it is a local problem, meaning very local, where the pipe is dumping it out right now,” Miller said.

The source of contamination at these beaches has not been identified by these advisories. We know from history that larger bacteria counts can come after a rain or ocean outfalls. At least one expert, though, says you can’t ignore the 800-pound gorilla in the room. That, of course, is the thousands of gallons of sewage that comes from Mexico and down the Tijuana River into the ocean.

“It’s been going on, as you know, forever. For me, I am not surprised it makes its way up the coast,” said Dr. Kim Prather, an atmospheric chemist at UC San Diego.

Coincidently, Prather, whose team detected high levels of air pollutants in the Tijuana River Valley area last September, is tracking pollution travel paths in the ocean.

“An oil spill can be distributed over 100 square miles in one day, so why would this pollution not do that. That’s my question. That is our question,” Prather said.

A county spokesperson says the tests detect Enterococcus bacteria, pathogens that are disease producing bacteria or viruses. They come from many sources, including animal waste, storm water or humans. You may not know how to say or spell it, but you definitely don’t want to swim in it.

The county health department says swimming in water under an advisory can cause gastrointestinal issues, such as diarrhea and vomiting, or skin and ear infections.