To fix a broken faucet valve core, first shut off the water supply and disassemble the faucet. Use pliers or a wrench to remove the stem, exposing the valve core. Clean the seat with a seat wrench or file, ensuring no debris remains. Insert a new valve core, aligning it properly, and secure it with a compression ring. Apply lubricant to the stem and reassemble the faucet, testing for leaks. If the seat is damaged, replace it with a new one.

Valve core failures often stem from mineral buildup or wear, leading to leaks and reduced water flow. According to the Environmental Protection Agency (EPA), hard water causes 85% of plumbing issues in regions with high mineral content, accelerating valve core degradation. A 2021 study by the National Association of Home Builders found that 60% of faucet leaks are due to faulty valve cores, costing homeowners an average of $300 annually in repairs and water waste. Replacing the valve core restores proper pressure and prevents further damage, as a well-maintained faucet operates 30% more efficiently. DIY repair saves 70% of professional costs (average $200–$500 vs. $600–$1,500), per data from the American Water Works Association. Regular maintenance, including annual seat inspections and lubrication, extends faucet lifespan by up to 10 years, reducing long-term expenses and environmental impact.