A new function, the reference function, is introduced for combined use with the hodograph. The function is applicable to two‐dimensional problems of steady groundwater flow through homogeneously permeable porous media. The reference function is applicable to all problems of the above class with the restriction that the boundary in the hodograph plane be composed of segments of straight lines and circular arcs. The function is determined by application of elementary conformal transformations. Use of the reference function is illustrated for the case of unconfined flow toward a riverbank. A graph is presented that gives the length of the seepage face as a function of the flow parameters. The approach for solving the general problem of the above class by use of the reference function is outlined.