A plumbling fitting in the form of an elbow or bend is formed of standard radius at the extrados in order to provide a fitting of minimal size, and, is expanded outwardly intermediate its ends at positions other than at the extrados, in order to increase the internal cross-sectional area of the elbow or bend intermediate the ends thereof and minimize pressure losses in the elbow or bend. A major portion of the cross sectional area is located in the vicinity of the extrados, thus positioning the centroid of that area and the longitudinal axis of the elbow or bend at a location displaced towards the extrados and displaced radially outwardly along the radius of the extrados, thus providing a reduced pressure loss comparable to an elbow or fitting of larger size.