of leaks between components one skilled in the art will also appreciate that a diaphragm may also be included in this embodiment of the present invention that is cut away to provide an opening 106 after testing is performed referring now to fig1 and 11 the drain assembly 110 for interconnecting the bathtub to the plumbing system of one embodiment of the present invention is shown here similar to the overflow assembly the drain assembly must be rigidly interconnected to the bathtub 6 thus embodiments of the present invention employ a drain assembly 110 wherein the tub floor 114 is sandwiched between a drain pipe flange 118 and a nut 122 in operation the drain pipe flange 118 includes a cylindrical portion 126 extending therefrom that includes a plurality of threads 130 the drain pipe flange 118 is mated with a drain pipe 134 wherein the nut 122 is threaded on the drain pipe 134 prior to the marriage of the cylindrical portion 126 and the drain pipe 134 the nut 122 is brought up to the threads 130 and tightened such that the tub floor is sandwiched between the drain pipe flange 118 and the nut 122 to secure the drain assembly to the drain port 10 of the bathtub 6 to test the system a membrane 138 may be employed to block flow to the drain pipe 134 after testing is completed a cover 140 and drain closure 144 which are common in the art may be incorporated referring now to fig1 15 a method of facilitating interconnection of the overflow pipe 22 and the drain pipe 134 is provided.