To replace a valve core in a household faucet, first shut off the water supply and drain excess water. Disassemble the faucet by unscrewing the handle, escutcheon plate, and stem. Use pliers to remove the old valve stem and core. Insert the new core into the stem, ensuring it seats properly. Reassemble the faucet in reverse order, tightening components securely. Test for leaks by turning on the water and checking for drips.

Replacing a valve core is critical because a damaged or worn core causes water waste and reduces faucet performance. According to the Environmental Protection Agency (EPA), household leaks can waste approximately 10,000 gallons of water annually, equivalent to the annual water use of a typical family of four. A faulty valve core results in continuous dripping, which not only increases water bills but also risks pipe corrosion and mold growth. A 2021 study by the American Water Works Association found that 30% of residential water loss stems from leaks, with valve core issues being a leading cause. Replacing the valve core is cost-effective, as it typically costs $10–$30 compared to $100–$300 for faucet replacement. Additionally, DIY repair reduces landfill waste and promotes sustainability. The EPA’s WaterSense program estimates that fixing leaks can save homeowners $100–$350 annually on water bills. Regular valve core maintenance ensures optimal water flow, prevents unnecessary expenses, and supports long-term plumbing system durability.