Drinking water sources have monitored total chromium since the 1970s, and the results of monitoring have been maintained in the Drinking Water Program's database since 1984.  Of 11,785 sources sampled for total chromium through 2001, detections were reported for 1,311 sources (1,227 ground water and 84 surface water sources).  The detection level for purposes of reporting (DLR )for total chromium is 10 µg/L.  

Until DHS required monitoring for chromium-6 under the UCMR, little information was available about the presence of chromium-6 in drinking water supplies. DHS performed limited analyses from 1997-2000 to determine the fraction of total chromium that is chromium-6, with the following results.  For these samples, not detected (ND) indicates chromium-6 at <0.5 µg/L.