Occoquan Reservoir; low-flow protections for drinking water safe yield. Requires any Virginia Pollutant Discharge Elimination System Permit issued after July 1, 2026, authorizing the diversion of sewage or reclaimed water from a publicly owned treatment works for reuse that would otherwise discharge into the Occoquan Reservoir, the Occoquan River, Bull Run, or any of their tributaries above the Occoquan Reservoir to incorporate certain low-flow protection requirements for drinking water safe yield if the total diversion amount allowed by the permit exceeds 500,000 gallons per day. The bill also prohibits the issuance of any Virginia Water Protection Permit after July 1, 2026, authorizing the withdrawal of water for consumptive uses from the Occoquan Reservoir, the Occoquan River, Bull Run, or any of their tributaries above the Occoquan Reservoir for any purpose other than agricultural or irrigation purposes or for continued operation, expansion, or relocation of existing public water supply withdrawals.