The movement of viruses in soil has important implications for land treatment of waste water. An adsorption mass transfer model is developed to describe the movement of single virus particles through packed beds of soils and soil components. The model predicted that ox0174 bacteriophage will breakthrough one meter of silt loam soil in 60 days for percolation rates of about 40 in/wk. Experimental determinations of equilibrium adsorption parameters for particular virus/adsorbent combinations are required to make similar predictions for enteric virus breakthrough from soil columns. Experimental measurements for attenuated poliovirus I (a typical enteric virus) show that: (1.) single virus particles are likely to be present in treated wastewaters that are land spread, (2.) poliovirus association with sand is about 50-fold stronger than ox-174 phage association with silt loam soil, and (3.) poliovirus interaction with 1-2 um montmorillonite clay particles is affected by clay aggregation at high virus titers. The needs for future research are indicated. These include measurements of enteric value inactivation in soil-water and incorporation of inactivation kinetic expressions in future versions of the adsorption mass-transfer model.