Mathematical models of flow in a saturated, inclined soil slab with an impermeable lower boundary have contributed substantially to understanding of important processes in the environment. One such process is movement of chemicals induced by interflow in sloping soil. Certain aspects of previous mathematical treatment regarding the inclined soil slab problem have, however, escaped scrutiny. The original 1965 treatment includes a peculiar quadratic boundary condition term that applies over a vanishingly small fraction of the soil surface. The quadratic term is shown to be unjustified and unnecessary in obtaining practical solutions. Mathematical solutions of two more general inclined slab geometries, three-dimensional and parallelogram slabs, are presented and solved. The solutions are illustrated in terms of figures showing selected flow paths and equipotentials. ¿ 1999 American Geophysical Union