three. What is EPA's authority for getting this action? EPA is using the SDWA § 1445(a)(2) authority as the foundation for monitoring the unregulated contaminants proposed below this rule. As part of its tasks below the SDWA, EPA implements § 1445(a)(2), Monitoring Program for Unregulated Contaminants. The SDWA, as amended by Section 2021 of America's Water Infrastructure Act of 2018 (AWIA) (Pub.