Radar rainfall is a source of high-resolution rainfall that is representative over areas ranging from small urban catchments to large river basins. The NEXRAD radar system deployed coast-to-coast in the United States is an important source of rainfall information for a variety of users. A common requirement among users is the need to know where, when, and how much rainfall fell, or is falling in real-time. Customization and post-processing of specific NEXRAD products takes into account precision, accuracy, spatial resolution, and beam altitude requirements. Spatial resolution, temporal updates, and beam altitude can impose limitations on the suitability of the radar data in specific applications. Achievable accuracy standards are affected by the data precision of measured reflectivity. To quantify potential differences between two products, with high and low precision, rainfall rates are compared during Tropical Storm Allison, which caused extensive flooding in Houston, Texas, June 5-9, 2001. Even when radar bias is corrected using rain gauges, low-precision data can introduce significant truncation errors over specific watersheds. This paper examines these key radar rainfall characteristics that affect applicability and suitability for specific uses.