A low-profile arch-shaped wastewater leaching chamber having asymmetric corrugations running transversely along the length of the chamber, where each corrugation has a wide section with a straight sidewall on one side, a substantially flat top portion, and a tapering downward extending curved section on the opposed side of the chamber. Each corrugation is reversed in orientation and transversely offset relative to adjacent corrugations, such that the curved tapering section of each corrugation is significantly inset from adjacent wide sections toward the center of the chamber body.