Drinking water; Occoquan Reservoir PFAS Reduction Program established. Creates the Occoquan Reservoir PFAS Reduction Program to reduce excessive levels of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in public drinking water derived from the Occoquan Reservoir. The bill requires certain facilities to monitor for PFAS on or before October 1, 2025, using the U.S. Environmental Protection Agency's Method 1633 or an alternative method approved by the EPA. The bill requires any such facility to report all results to the Department of Environmental Quality no later than the tenth day of the next month after the month in which the result is reported by the laboratory and to include in such report all PFAS analytes measured by the test method. The bill requires by July 1, 2027, for any facility that measures exceedances in its discharge of the maximum contaminant level (MCL) for PFAS in drinking water promulgated on or before January 1, 2025, the Department, for an individual Virginia Pollutant Discharge Elimination System permit if the facility discharges directly to surface waters, or a major publicly owned treatment works, for an indirect discharger, to modify the applicable discharge permit to require that the facility's discharge not exceed that MCL. The bill requires the modified permit to provide a compliance schedule that requires compliance with such level as soon as possible but no later than July 1, 2029. The bill exempts from its provisions any industrial discharger not listed in the bill, any publicly owned treatment works or drinking water treatment plant, or a municipal solid waste facility but provides that any public water system may follow the requirements of the bill for the purpose of planning for compliance with the MCL for PFAS in finished water. The bill clarifies that its provisions will not limit the authority of the Department or the owner or operator of any publicly owned treatment works to which any user discharges wastewater to require monitoring or reporting or otherwise regulate the discharge of any PFAS chemicals or other pollutants under other applicable legal authority.