A containment system includes a rotationally molded polymeric base unit in the form of a tub having an open top. The base unit includes a generally L-shaped rim at the open top comprised of an upwardly extending section that terminates in a cut edge and an inwardly extending section. The containment system also includes at least one perforated grate having a top side, a bottom side and a peripheral edge. The at least one perforated grate is supported, at least in part, by the inwardly extending section of the rim in such a manner that a container can be supported on the top side of the grate above the tub.