The objectives of this manuscript are to outline a procedure for locating and sizing septic tank filter fields and to evaluate the performance of filter fields designed by this approach. The limitations on effluent loading due to the crust which forms at the gravel-soil interface have long been recognized. Our previous research has shown that in many soils, effluent must be stored in the filter field during periods of hydraulic stress. Thus, the hydraulically limiting factor for filter field loading rates is either transmission by the crust or storage of effluent within the filter field, whichever is most limiting. This approach, the storage-crust approach, uses soil features to estimate the amount of storage needed and the design to achieve the needed storage or the design to accommodate crust transmission rates if crusting is limiting. A 13% sample of 190 filter fields which were designed by the storage-crust technique indicated no failures. Also, no failures have been reported by personnel of the Arkansas Department of Health.