Frequent Questions

What is the difference between the Central Data Exchange (CDX), the Safe Drinking Water Accession and Review System (SDWARS) and the National Contaminant Occurrence Database (NCOD)?

CDX is an electronic data receiving system for most environmental compliance reporting, including UCMR. UCMR data entered into CDX is stored in SDWARS, which is the information system that supports the collection of data for the UCMR. Data in SDWARS is made publicly available through the NCOD. NCOD contains occurrence data about regulated and unregulated contaminants. (Implementation Guidelines for SDWARS/UCMR Volume I: Introduction to CDX and UCMR Submissions, EPA816-R-01-022A, December 2001).
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