A system for cleaning and maintaining a vault includes a vault that may have equipment submerged in water. The vault includes a floor, at least one wall, and a cover that collectively define a vault interior. In some versions there is contaminated water in the vault that is at least one foot above the lowest point on the vault floor. In some versions, the water may be 12 to 14 feet above the lowest point on the floor. A portion of the floor may slope toward a vacuum head that is indirectly coupled with a source of suction. In some versions, at least the vault floor is lined with a liner that has a low coefficient of friction and is corrosive resistant. The source of suction may be a vacuum hose of a vacuum truck.