; and (B) beginning on the date test methods are validated under paragraph (4), monitoring for the total amount of all perfluoroalkyl and polyfluoroalkyl substances with at least one fully fluorinated carbon atom. (4) Validated test methods Not later than two years after the date of enactment of this subsection, the Administrator shall validate one or more test methods for monitoring the total amount of all perfluoroalkyl and polyfluoroalkyl substances with at least one fully fluorinated carbon atom in public water systems. (5) Authorization of appropriations There are authorized to be appropriated $10,000,000 for each of fiscal years 2021 through 2031 to the Administrator to pay the reasonable cost of such testing and laboratory analysis as are necessary to carry out monitoring required under this subsection by public water systems serving fewer than 10,000 persons. .