In 1991, as part of the SDWA, the EPA placed chromium under its list of maximum contaminant level goals (MCLG), to have a maximum contaminant level (MCL) of 100 ppb.[41] In 1996, the SDWA was amended to include a provision known as the Unregulated Contaminant Monitoring Rule (UCMR).[42] Under this rule, the EPA issues a list of 30 or less contaminants that aren't normally regulated under the SDWA. Chromium was monitored under the third UCMR, from January 2013 through December 2015.[42] The EPA uses data from these reports to assist in making regulatory decisions.