The advisory affects all San Diego County beaches and bays, with heightened risks near storm drains and outlets. Elevated bacteria levels can lead to illnesses for swimmers, surfers, and divers. Specific sites, such as La Jolla Cove and Coronado Shoreline, are under stricter advisories due to excessive contamination. Residents and visitors are urged to avoid water activities during rainfall and for 72 hours afterward to minimize health risks.