In addition to pressure testing of the drainage system, the shower pan itself needs to be tested for leaks. In this test, the shower drain is plugged and the pan is filled with water. The water is allowed to stand in the pan, and the pan is checked for leaks. Ideally, the same shower drain test plug can be used for both pressure testing of the drainage system and leak testing of the shower pan.
FIG. 7 shows an alternative embodiment of the shower drain test plug 1 which is designated herein as plug 101. The plug 101 is similar to the plug 1 except that it is adapted to engage and seal against the upper annular wall 25 of the drain body, instead of sealing against the side wall 23. Like the plug 1, the plug 101 includes an upper threaded portion 165 having external threads 167 sized to engage the internal threads 37 of the aperture 35. A top wall 169 sealingly covers an upper end of the threaded portion 165. Gripping means 171 are provided on the plug 101 for gripping by hand or with a wrench, pliers, or the like for turning the plug 101 in the aperture 35. A cylindrical extension 173 extends downwardly from the threaded portion 165 to a sealing portion 175 proximate a lower end 177 of the plug 101.