To replace a leaking pipe under a sink, first shut off the water supply by turning clockwise on the shut-off valve near the wall. Disconnect the supply lines using a wrench. Remove the damaged pipe by cutting it with a pipe cutter or hacksaw. Apply pipe dope or PTFE tape to the threads of the new pipe before connecting it to the shut-off valves and faucet. Tighten securely with a wrench but avoid over-tightening. Reconnect the supply lines, turn the water back on, and test for leaks by running the faucet. If leaks persist, inspect connections and repeat as needed.

Leaky pipes under sinks are a common issue due to corrosion, mineral buildup, or worn components. According to the Environmental Protection Agency (EPA), household leaks can waste an average of 10,000 gallons of water annually, costing homeowners up to $100 in water bills. The American Water Works Association (AWWA) estimates that 15% of residential water usage stems from leaks, emphasizing the importance of timely repairs to prevent property damage. Water damage from leaks can lead to mold growth, structural decay, and increased insurance premiums. A study by the Insurance Institute for Property Loss Prevention found that water-related damages account for 22% of all homeowners insurance claims, averaging $5,000 per claim. Proactive replacement of failing pipes with durable materials like copper or PEX reduces long-term costs and environmental impact. The EPA recommends replacing old pipes every 20–30 years, as corrosion and wear degrade their integrity over time. Proper installation techniques, such as using pipe sealants and torque wrenches, ensure leak-free connections, extending the lifespan of plumbing systems. Neglecting repairs can escalate minor issues into costly emergencies, underscoring the need for prompt, expert-led replacements.