A day at the beach is supposed to be relaxing. But for anyone planning a trip to Imperial Beach in California, that swim could come with a serious health warning attached.
Imperial Beach, located just south of San Diego, has been named one of the worst beaches in the entire United States for bacteria contamination, according to a new report from the Surfrider Foundation. Investigators found a bacteria rate of 89 percent at the beach, the highest of any beach in California, a number calculated from the sheer amount of time the beach has spent closed due to unsafe water.
What’s actually in the water
Local environmental watchdog San Diego Coastkeeper has already marked Imperial Beach as closed, citing the risk of raw waste or hazardous runoff reaching the shoreline right now. That closure covers a long stretch of coast, running from the south end of Seacoast Drive all the way north past Carnation Avenue.
The County of San Diego’s own Beach & Bay Water Quality Monitoring Program backs this up, flagging Imperial Beach and several nearby areas as closed because recent testing showed the water fails to meet safety standards. For anyone over 50, whose immune systems may not bounce back from illness as quickly as they once did, wading into water like this could mean far more than a ruined vacation day. Exposure to contaminated coastal water has been linked to stomach illness, skin infections, and other complications that can hit older adults especially hard.
This is not a new problem
Imperial Beach has struggled with contamination for years. Last year, the Surfrider Foundation also named it one of the most contaminated beaches in the country, though the bacteria rate at that time was somewhat lower, at 82 percent. The trend, in other words, is moving in the wrong direction.
There has been an effort to respond. In 2025, a new water testing lab was set up in Imperial Beach through a partnership between the San Diego Chapter’s Clean Border Water Now program and the local YMCA’s Camp Surf. Whether that translates into cleaner water anytime soon remains to be seen.
Still tempting travelers despite the risk
Even with the warnings, Imperial Beach continues to draw visitors who may not realize what they are walking into. The beach has a pier with a lookout point offering sweeping views of the San Diego coastline, along with the kind of classic boardwalk attractions that make a beach town feel inviting, including an ice cream shop and a gift shop. For older travelers hoping to enjoy the scenery without stepping foot in the water, those spots may be the safer bet.
California is far from alone
Anyone assuming this is a California specific problem should think again. Hawaii, often marketed as a pristine paradise, is now home to two of the most contaminated beaches in the entire country. Oahu’s Punaluʻu Beach Park and Kauai’s Moloaʻa Stream Mouth both recorded a bacteria rate of 100 percent, landing them at the very top of the national list.
Back on the mainland, the danger does not stop at Imperial Beach. Linda Mar Beach in Pacifica ranked as the second most contaminated beach in California, with a bacteria rate of 72 percent. San Luis Creek at Avila Beach, in San Luis Obispo County, followed close behind at 47 percent.
For travelers planning a coastal getaway this season, the message is clear. A beach that looks calm and inviting on the surface may be hiding a water quality problem that could turn a relaxing trip into a health scare.