A prefabricated in-wall water service box with a five sided deep drawn stainless steel enclosure that has an open side with a reservoir lip and three closed sides integral with a top and bottom so that a reservoir is formed that is drained through a drain hole into a stainless steel nipple that is welded to the bottom and extends downwardly from the drain hole while hot and cold water control valves are mounted inside the enclosure through holes to a fittings located outside the enclosure at its two side walls. A trim bezel with a planar facing flush with a mounting wall is secured to the enclosure when it is mounted to two studs by two mounting brackets affixed to the two side walls by stainless steel screws. The hot and cold water control valves are ninety degree stainless steel ball valves while the brass hot and cold water fittings are a ninety degree elbow connected to an extension nipple that can accept a sweated copper connection, a compression fitting and a direct pipe thread connection while the side walls, the bottom and the top are joined with the back wall by four ninety degree radius turns.