for easy mounting in building wall structure while accommodating the presence of water lines and the like that may be disposed in the wall structure directly behind the box since the valve shanks 35b extend horizontally and because there is room in the wall behind the outlet box 10 the water supply lines can be connected from any direction i e extending vertically from above or below or horizontally from the left or the right conventional washing machine outlet boxes orient the valve shanks vertically and have no space in the wall behind them therefore the plumber has to route supply lines around and to the valve shanks with extra pipe elbows and pipe sections this requires more soldering or adhesion welding and presents the possibility of more leaks the peripheral wall 20 is formed of the peripheral forward edge 22 in a rounded curved configuration folding or extending back so that the mounting flanges 24 26 and 28 are spaced back of the forward edge 22 as shown in fig2 and 3 this positions the mounting flanges behind suitable wall board this enables the mounting of the box 10 with wall board panel 38 extending to a position flush with the peripheral forward edge 22 the lower bottom wall section 16 is formed with an outlet aperture 40 fig1 accommodating a drain line outlet the drain line outlet is provided with a suitable mount such as with a tubular sleeve 42 fig2 of abs or pvc that surrounds a sheet metal tube 44 the tube 44 is clamped at the opposite ends such as by crimping to form flanges 46 and 48 over the ends of the sleeve 42 and within the peripheral edge of aperture 40 this provides an outlet coupling to which.