What is the recommended procedure when you have a leaking cold water joint on a copper pipe?

• A. Immediately isolate the supply, drain down.
• B. Repair by replacing the entire copper run.
• C. Immediately isolate the supply, drain down, fix or replace the joint using a soldered, crimped, or compression method, and test for leaks.
• D. Apply duct tape to seal the leak.

Answer: (C)

When a cold water copper pipe joint leaks, the priority is to stop water flow and restore a secure seal. The best approach is to immediately isolate the supply, drain the line to reduce pressure and dry the work area, then fix or replace the joint using a proper method—soldered, crimped, or compression—that creates a true seal. After completing the repair, test for leaks before restoring full pressure.

Why this works: shutting off the supply and draining minimizes the risk of water damage while you work, and using a correct joint method ensures the connection is watertight and durable. Soldered joints require clean, dry copper and proper flux and heating; compression or crimp joints use fittings designed to seal under pressure. Testing afterward confirms the repair is solid and there’s no ongoing leak.

Duct tape or quick fixes aren’t reliable for a live water leak, and replacing the entire run is usually unnecessary unless the pipe or many joints are compromised.