Abstract: A trench drain system and method of installation thereof on a level floor surface. An elongate channel member is placed on the floor surface. A preformed elongate sloping member having a thick end tapering to a thin end in inserted into the channel with its thin end closest to the channel drain opening, thereby forming an inclined sloping surface. A grate extends over the channel inlet. The area adjacent the channel is filled to the height of the channel, whereby water thereon flows through the grate into the channel, along the inclined surface and out through the drain opening. The channel can be placed adjacent a vertical wall whereby wall tile may be installed over a channel top edge. The floor area adjacent the channel is filled with preformed sloping sheet members or with plastically formable material positioned at an incline using a floor height setting post.