According to the 2026 Heal the Bay Beach Report Card, several California beaches consistently struggle with high levels of "fecal indicator bacteria," especially after rain events. The most frequent "Beach Bummers" include the Santa Monica Pier in Los Angeles County, which often ranks near the top due to urban runoff and bird populations. In San Diego County, the Tijuana River Mouth and Imperial Beach are frequently closed or under advisory because of cross-border sewage issues. Other problematic spots in 2026 include Mother's Beach in Marina del Rey (due to poor water circulation) and Linda Mar Beach in San Mateo County. Bacteria levels typically spike within 72 hours of rainfall as storm drains carry animal waste and sewage overflow directly into the ocean. Health officials advise swimmers to look for posted "Warning" or "Closed" signs and to use the digital Beach Report Card app to check real-time water quality grades (A through F). In 2026, climate-driven "extreme rain events" have made these bacterial spikes more common, making it essential to check the water quality before diving in.