EPA Region 6 issued a Administrative Order (AO) under its authority pursuant to 414(g)(3) of the Safe Drinking Water Act, 42 U.S.C. ? 300g-3(g)(3) to the City of Plains located in Plains, Texas. The AO was issued in response to violations of: 40 C.F.R. ? 141.62(b)(16) for the Maximum Contaminant Levels (MCL) for arsenic and fluoride. The AO requires the City of Plains to follow the system's proposed construction schedule to achieve compliance with the MCLs.