San Francisco seems to be operating in a 'business as normal' situation.
By the time of The Walking Dead, just like Los Angeles, San Francisco was engulfed in chaos and destruction during the outbreak and therefore became overrun by the dead. San Francisco was declared overrun and as a result, completely burnt down, in accordance with the regulations of Operation Cobalt. A few survivors managed to escape San Francisco, considering Travis' group stumbled upon the remains of a destroyed boat with logs stating the city of San Diego was completely burnt.
The ship log that Nick picked up from the overturned ship reveals that San Francisco has been destroyed by the military.