A vapor delivery system and method is provided that is adapted for ablating bladder tissue to treat overactive bladder (OAB). The vapor delivery system includes an anchor tip configured anchor the system in the bladder while condensable vapor is delivered to target tissue. In one method, the vapor delivery system is advanced transurethrally into the patient to access the target tissue of the bladder, which can include a surface sensor of the bladder responsible for creating an urge incontinence sensation. The vapor delivery system includes a vapor source that provides a high quality vapor for delivery to tissue.