A method for mounting a kit for fixing a tap to a partition , particularly to a plasterboard partition, this method comprising the successive steps of: a) pre-mounting at least one connector of the kit to a plate of the kit, each connector comprising a first endpiece for connection to a water supply pipe and a second nozzle for connecting the valve, the second endpiece defining a longitudinal axis (X214), having an outer surface of polygonal section and having an outer thread, b) connecting each connector to a corresponding water supply pipe , c) making at least one hole in the partition for the passage of the second endpiece of each connector through the partition, d) placing the partition in front of the plate , e) pulling the second connection endpiece of each connector through the at least one hole of the partition , and f) fixing the plate on a rear face of the partition, on the side opposite the location provided for the tap, characterized in that : - between steps e) and f), the method comprises a step consisting in adjusting the length over which each second endpiece protrudes axially relative to a front face of the partition , whereas the second endpiece of each connector is received inside a corresponding ring of the kit attached to the plate during the pre-mounting of step a), the ring having an inner contour complementary to the outer shape of the endpiece , the ring blocking the rotation of said second endpiece about its longitudinal axis (X214), but not preventing the second endpiece from sliding parallel to the longitudinal axis (X214), and - step f) comprises immobilizing each second endpiece along its longitudinal axis (X214), using a respective nut , the nut being screwed around said second endpiece , then screwed to the corresponding ring , each nut bearing against the front face of the partition . a) pre-mounting at least one connector of the kit to a plate of the kit, each connector comprising a first endpiece for connection to a water supply pipe and a second nozzle for connecting the valve, the second endpiece defining a longitudinal axis (X214), having an outer surface of polygonal section and having an outer thread, b) connecting each connector to a corresponding water supply pipe , c) making at least one hole in the partition for the passage of the second endpiece of each connector through the partition, d) placing the partition in front of the plate , e) pulling the second connection endpiece of each connector through the at least one hole of the partition , and f) fixing the plate on a rear face of the partition, on the side opposite the location provided for the tap, - between steps e) and f), the method comprises a step consisting in adjusting the length over which each second endpiece protrudes axially relative to a front face of the partition , whereas the second endpiece of each connector is received inside a corresponding ring of the kit attached to the plate during the pre-mounting of step a), the ring having an inner contour complementary to the outer shape of the endpiece , the ring blocking the rotation of said second endpiece about its longitudinal axis (X214), but not preventing the second endpiece from sliding parallel to the longitudinal axis (X214), and - step f) comprises immobilizing each second endpiece along its longitudinal axis (X214), using a respective nut , the nut being screwed around said second endpiece , then screwed to the corresponding ring , each nut bearing against the front face of the partition . <EOS>