The National Chromium and Boron Occurrence Survey (NCBOS) specifically addressed the following questions: What are the analytical method challenges and sensitivities for reliable low-level detection of chrome species and boron in drinking water supplies; What are the national occurrence patterns for chromium species and boron in drinking water sources; and, What is the fate of these compounds through drinking water facilities and distribution systems? This project investigated analytical challenges for both chromium and boron analysis. The investigation focused on interferences, preservation techniques, and digestion methods for accurate and repeatable recovery performance. Laboratory experiments were first used to investigate the analytical challenges. Preliminary field sampling based on knowledge gained from the laboratory experiments validated the analytical methods used for the regular survey. Interferences in boron analysis were found with aluminum and iron for at least one spectrum evaluated when background concentrations approached 100 mg/L as either Fe or Al. Therefore at least two spectra were used to confirm all boron analyses. Boron was found to be otherwise unaffected by sample handling and processing methods as long as base preservation methods were employed (pH > 8). Sampling for chromium necessitated consideration of both total chromium and hexavalent chromium analyses. Previous field sampling experiences had resulted in total chromium concentrations less than corresponding hexavalent chromium concentrations (Eaton et al. 2001). A series of lab experiments were conducted to determine the best approach for chromium analysis to correctly quantify both hexavalent and total chromium. Using in-bottle acid digestion procedures that follow Method 3500-Fe B (Standard Methods 1998) - the hydroxylamine digestion for iron solublization - was found to perform best in achieving complete recovery of total chromium. Base preservation for hexavalent chromium was found to be adequate when the sample pH was raised above pH 8. The final survey sample kit preservation, digestion procedures, and sample analysis procedures were developed based on results from the investigation of both chromium and boron analytical challenges. Includes 4 references, tables, figures.