The most significant feature of all granular media problems encountered in rapid sand filter plants is the time it takes for a problem to develop. It may take months, or even years, before media problems become evident. The basics of media technology and design are reviewed along with descriptions of six case histories that, for all practical purposes, cover the gamut of granular media problems that may be encountered in the operation of water treatment plants today. Protocols are then recommended for strengthening present filter media standards and for avoiding or minimizing both common and uncommon media problems in the installation of media and in the operation and maintenance of water filtration plants. Topics covered include solids separation (entrapment, sedimentation, attachment); physical features affecting media design and performance (fixed bed porosity, media grain size, media shape, media density, friability); backwash requirements, including air scour; and media arrangements (multiple media, deep bed media). Case studies cover improper size of filter media, poor dual media match, old media and wear over time, caked media and anthracite breakdown, slime growth and single media wear, and poor friability and media breakdown. Recommended protocols for standards for filter media, installation, and operation and maintenance are listed.