A computer application called Chemical Help was developed to facilitate review of reports for the National Highway Runoff Water-Quality Data and Methodology Synthesis (NDAMS). The application provides a tool to quickly find a proper classification for any constituent in the NDAMS review sheets. Chemical Help contents include the name of each water-quality property, constituent, or parameter, the section number within the NDAMS review sheet, the organizational levels within a classification hierarchy, the database number, and where appropriate, the chemical formula, the Chemical Abstract Service (CAS) number, and a list of synonyms (for the organic chemicals). Therefore, Chemical Help provides information necessary to research available reference data for the water-quality properties and constituents of potential interest in stormwater studies. Chemical-Help is implemented in the Microsoft-help system interface.