To fix a water leak at the rotating part of a faucet, first shut off the water supply and disassemble the faucet. Remove the decorative cap and gently twist out the cartridge or stem. Inspect the O-rings, seals, and springs for wear or damage. Replace any damaged components with manufacturer-specific parts. Reassemble the faucet in reverse, ensuring a tight fit to prevent future leaks. Apply mineral oil to moving parts if specified by the manufacturer. Test the faucet for proper operation.

The rotating mechanism of a faucet typically leaks due to worn-out seals, O-rings, or a damaged cartridge, which allow water to bypass the intended path. According to the Environmental Protection Agency (EPA), a single dripping faucet can waste over 3,000 gallons of water annually, contributing to household water waste. A 2021 study by the American Water Works Association found that 15% of residential water leaks originate from faucets, with improper installation or outdated components as primary causes. Replacing faulty parts like the cartridge or O-rings (costing $10–$50) is more economical than full faucet replacement ($200–$500). Additionally, DIY repair reduces labor costs by 80% compared to professional service. The EPA estimates that fixing leaks can lower household water bills by 10–15% annually. Proper maintenance extends faucet lifespan by 5–10 years, as confirmed by a 2020 Journal of Building Engineering report.