To repair a double-handled, double-hole faucet valve core, first shut off the water supply and drain excess water. Remove the faucet handles and escutcheon plates using a screwdriver. Locate the valve stem and retaining nut, then loosen and remove the stem. Inspect the seat and replace any damaged O-rings or seals. Clean the seat with a seat wrench or file if it’s rough. Insert a new valve core, ensuring it’s seated properly, and tighten the retaining nut. Reassemble the faucet by reversing the disassembly steps. Apply a thin layer of plumber’s grease to moving parts for smooth operation. Test the faucet for leaks by turning on the water and checking under the sink.

This repair is critical because a failing valve core causes significant water waste and increases utility bills. The Environmental Protection Agency (EPA) estimates that household leaks can waste over 10,000 gallons of water annually per household, translating to hundreds of gallons lost monthly. A faulty valve core allows constant water flow even when the faucet is off, leading to exponential waste. Additionally, repeated leaks can damage underlying flooring, walls, and infrastructure, costing thousands in repairs. Replacing the valve core is cost-effective compared to replacing the entire faucet, with kits typically costing under $20. Data from the EPA’s 2022 WaterSense report shows that fixing leaks can reduce water consumption by 10–15%, saving homeowners an average of $100 annually. Proactive valve core maintenance ensures optimal performance, energy efficiency, and long-term cost savings, making it a priority for homeowners and plumbers alike.