Several radionuclides such as radon, radium, uranium, alpha emitters, and beta and photon emitters are to be regulated by the US Environmental Protection Agency under the Safe Drinking Water Act. When water treatment plants remove these contaminants from drinking water sources, the contaminants get transferred to the treatment plant residuals such as wash water, brines, and sludges. The presence of radionuclides in treatment plant wastes, depending on the concentration relative to allowable limits, may limit the use of less expensive disposal options for those residuals, thereby increasing the costs. Depending on the concentration of co-contaminants in residuals, thereby increasing the costs. Depending on the concentration of co-contaminants in residuals, the residuals might be classified as hazardous under the Resource Conservation and Recovery Act (RCRA). The cost of residuals disposal is also a function of the volume (and/or mass) of the residuals. Therefore, it is important to estimate the quantities, radionuclide concentrations, and co-contaminant concentrations of residuals generated from water treatment plants that remove naturally-occurring radionuclides. The Spreadsheet Program to Ascertain Residuals radionuclide Concentrations (SPARRC) can be used to estimate the waste volumes and concentrations of radionuclides (and be used co-contaminants) in the residuals from water treatment plants removing naturally-occurring radionuclides. This computer program has been developed in support of the EPA's revision to the 1990 document entitled 'Suggested Guidelines for the Disposal of Drinking Water Treatment Wastes Containing Naturally Occurring Radionuclides'.