The arson was one of several that have occurred in the area recently, including one at a hotel Thursday night and one in a public restroom on Monday, South San Francisco police Sgt. Joni Lee said.
The carwash's security camera showed an Asian female in her late teens to early 30s wearing a light-colored baggy hooded jacket with dark lining, police said.
She was wearing sunglasses on her head and carried a light-colored bag that contained items for starting fires.
The carwash arson was reported at 9:39 p.m., about 40 minutes after an arson was reported at a nearby hotel at 800 El Camino Real, Lee said.
Six bags of linens sitting outside the hotel were set on fire, Lee said. Police think the same person committed both crimes.
On Monday, a paper toilet seat cover in an Orange Park bathroom was lit on fire at about 8:15 p.m. Police said it might have been the same individual responsible for Thursday's arsons.
Lee said the fires have caused only minor damage.