Patent ID: 8864418

Claim:
A method for rehabilitating an underground water conduit having at least one service entrance, the method comprising: plugging the at least one service entrance with a plug having a light emitter which is responsive to the presence of an electromagnetic field; lining the internal surface of the underground water conduit with a semi-transparent membrane thereby covering the plug; generating an electromagnetic field with a coil inductor disposed on a drilling head having a drill bit, wherein the coil inductor is adapted to generate an electromagnetic field near the drilling head; moving the drilling head inside the underground water conduit until the light emitter of the plug is turned on by the electromagnetic field emitted by the coil inductor; aligning the drill bit with the light emitted by the light emitter through the semi-transparent membrane; and drilling the plug with the drill bit through the semi-transparent membrane in order to reopen the at least one service entrance.