'standard amount, for a distributor-retailer in relation to a charge for trunk infrastructure for its water service or wastewater service, means—
(a) if its participating local government for the area in relation to which the trunk infrastructure for the charge is supplied has made an adopted infrastructure charges resolution—the amount of the distributor-retailer's relevant proportion of the adopted infrastructure charge immediately before the resolution takes effect; or
(b) if paragraph (a) does not apply—the distributor-retailer's relevant proportion of the adopted infrastructure charge under section 648A(1)(b).
standard charge day, for a distributor-retailer, means the day a State planning regulatory provision (adopted charges) first has effect.'.