California law requires that a residential landlord is responsible for installing and maintaining at least one usable telephone jack and for placing and maintaining the inside telephone wiring in good working order. Thus, the answer is "no." Nevertheless, if you are willing to allow your tenant to have an additional telephone line installed, I recommend that you prepare a written agreement that provides permission for the tenant to have the installation done only by a licensed contractor who has your approval, or a phone company employee. The agreement should also state that the tenant will be exclusively responsible for the costs of installation as well as restoration of the premises without any damage caused by the installation. Make sure that the tenant signs the agreement before any work is commenced