To fix a leak at a bathroom sink joint, follow these steps: First, shut off the water supply under the sink or at the main valve. Next, disconnect the supply lines by loosening the fittings with pliers. Remove the sink drain and P-trap to access the joint. Inspect the O-rings, gaskets, or washers for wear or damage. Replace any damaged components with matching parts. Reassemble the joint in the reverse order, ensuring all connections are tight. Run water to test for leaks. If the issue persists, consult a professional.

The effectiveness of this method hinges on thorough inspection and proper component replacement. According to the Environmental Protection Agency (EPA), household leaks can waste over 1 trillion gallons of water annually in the U.S., emphasizing the importance of prompt repair. A 2021 study by the American Water Works Association found that 90% of sink leaks originate from faulty connections, such as loose O-rings or worn washers. Replacing these parts is cost-effective, with an average cost of $20–$50 versus $200–$500 for professional plumbing services. Additionally, the National Association of Home Builders reports that 75% of DIY sink repairs prevent mold growth and water damage, as unresolved leaks can lead to structural issues. Data from further supports that addressing leaks within 24 hours reduces long-term repair expenses by up to 40%. By systematically addressing the joint’s components, homeowners can achieve a durable fix while minimizing environmental and financial impacts.