This report focuses on the results of our own studies aimed at assessing the role of faults and fractures in controlling fluid flow through Navajo Sandstone exposed in Southern Utah (e.g., Shipton et al., 2002; Dunn, 2004). We, and others, have completed similar outcrop-based studies in faults found in sandstone and other rock types (e.g., Aydin, 1978; Forster and Evans, 1991; Antonellini and Aydin, 1994, 1995; Caine et al., 1996; Matthai et al., 1998; Forster et al., 1998; Caine and Forster, 1999; Davis, 1999; Taylor et al., 1999; Maerten et al., 2001; Jourde et al., 2002). The Big Hole Fault (Shipton et al., 2002) and Teasdale Fault Zone (Dunn, 2004) have received much of our attention over the past 5 years because they are well exposed at the surface and provide a wide spectrum of fault type within the relatively uniform sandstone host rock.