To preclude development of hydrostatic pressures within the reinforced soil mass of a mechanically stabilized earth structure, the design of the structure needs to provide appropriate drainage features. Typical drainage features include specifying free draining fill for the entire backfill, including free draining fill immediately behind the fascia; and/or including drains behind and/or beneath the reinforced soil mass. Free draining material is typically defined as the maximum percentage of fines content within the soil mass, which varies in the literature between zero and fifteen percent. For the drainage material to remain effective, appropriate filter criteria needs to be considered. While the percentage of fines content within the reinforced soil mass does influence the permeability of the soil mass and possibly reduce flux, the fines content of the soil could influence permeability of the drainage material if subjected to hydraulic flux. Accordingly, the fines content and permeability of the soils comprising the mechanically stabilized earth structure, including the drainage features should be understood so that a full understanding of the hydrostatic pressures can be determined. This paper presents a case history of a segmental retaining wall subjected to unanticipated saturation followed by fouling of the drainage material, which ultimately led to collapse of the structure. To provide acceptable performance of MSE walls, it is imperative that the wall have one of the following: (1) If possible, either provide grading of surface above the retaining wall such that drainage away from the wall is provided or provide a curb at the edge of paving to limit infiltration. (2) Require select granular fill with less than 15% fines for the reinforced zone soil. (3) Require gradation restrictions on soils adjacent to drainage aggregate such that gradational compatibility is achieved or protect the drainage aggregate with a properly designed geotextile. (4) Route infiltrated water towards the rear of the reinforced zone and drain into a chimney drain. Waterproof the top of aggregate used for compaction aid with either a geomembrane or a geosynthetic clay liner. (5) Increase minimum safety factors for connection strength to accommodate hydrostatic pressure within aggregate behind the wall fascia. (6) Provide additional reinforcement (i.e., decrease spacing) to reduce contributing area of hydrostatic pressure on the geogrid-masonry unit connections. Should the entire reinforced zone be subjected to inundation by either surface water infiltration, groundwater or adjacent bodies of water such as basins or streams, and the reinforced zone consist of soils not considered to be freely draining, design of the wall internal stability must also account for negative impacts on geogrid-soil interaction. Here buoyant unit weights need to be considered in determining geogrid-soil interaction and development lengths. Furthermore, it is possible the interaction coefficients could be reduced from typical values, which should be evaluated through appropriate testing.